feat(local-model): the pinned runtime, its supervisor and the runtime client

runtime.ts: the runtime is pinned in a compiled constant (version, URL, size,
sha256). The archive is streamed to a .partial file while it is hashed,
continued with a Range request, retried at most 3 times, and the hash is
compared before anything is unpacked; a mismatch deletes the file. It is
unpacked with /usr/bin/tar into a temporary folder and renamed.

The supervisor runs the runtime as a non-detached child with an environment
built from an allowlist by the pure runtimeEnv(), on a port chosen once by
binding. It restarts the child at most 3 times, stops it with SIGTERM, adopts
or replaces its own orphan on the port and answers port-in-use for any other
listener. parseInferenceComputeTotal() reads the device total the runtime
logs when it starts. Under vitest nothing spawns or fetches.

ollama-client.ts: the pull is parsed incrementally by a pure parser (a 23 GB
pull is about 1.4 million lines), with up to 5 retries on an error line or a
cut stream. verifyModel() loads the model with one tiny chat, checks what the
runtime reports (all on the GPU, the chosen context) and makes one tool
probe; each failure is a code.

developer-tools.ts: only /usr/bin/xcode-select -p, bounded, darwin only.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/local-model/developer-tools.ts

@@ -1,9 +1,6 @@
 /**
  * @fileoverview Whether this Mac has the developer tools a coding agent calls (git, Python).
  *
- * CONTRACT STAGE: the function below has its final signature and a body that throws; the body
- * is written next.
- *
  * Why it exists: on a Mac without Xcode or the Command Line Tools, `git` and `python3` are
  * stubs that open macOS's "install the command line developer tools" window. A coding agent
  * runs both, so the install window says one honest sentence when the tools are missing
@@ -15,19 +12,24 @@
  *  - macOS only. Anywhere else, and when the command does not answer in time, the answer is
  *    `unknown`, and nothing is said.
  *  - Never throws. The answer is cached for a short while, so a window that polls once a
- *    second does not spawn once a second.
+ *    second does not spawn once a second. Only `present` and `missing` are cached: an
+ *    `unknown` is asked again, because it says the check itself did not work.
+ *  - Under vitest the default `run` spawns nothing and answers "did not start", so a test
+ *    that wants an answer injects its own.
  */
 
+import { execFile } from 'node:child_process';
 import type { LocalModelDeveloperTools } from '../types.js';
 
-/** Marks a body the contract stage left unwritten. */
-function notImplemented(what: string, ..._args: unknown[]): never {
-  throw new Error(`${what} is not implemented yet`);
-}
-
 /** How long `/usr/bin/xcode-select -p` may take. */
 export const DEVELOPER_TOOLS_TIMEOUT_MS = 2_000;
 
+/** How long an answer is reused. Installing the tools takes minutes, so a minute of staleness is not seen. */
+const DEVELOPER_TOOLS_CACHE_MS = 60_000;
+
+/** The one command this module runs. It prints the active developer directory and exits 0, or exits with an error when there is none. */
+const XCODE_SELECT = '/usr/bin/xcode-select';
+
 /** What the check calls. Each member defaults to the real thing; a test injects its own. */
 export interface DeveloperToolsDeps {
   /** Default `process.platform`. */
@@ -36,7 +38,80 @@ export interface DeveloperToolsDeps {
   run: (file: string, args: readonly string[], timeoutMs: number) => Promise<number | null>;
 }
 
-/** `present` when `/usr/bin/xcode-select -p` exits 0, `missing` when it exits with anything else, `unknown` otherwise. */
+/** The default `run`: one bounded `execFile`, no shell. Spawns nothing under vitest. */
+function runBounded(file: string, args: readonly string[], timeoutMs: number): Promise<number | null> {
+  return new Promise((resolve) => {
+    if (process.env.VITEST) return resolve(null);
+    try {
+      execFile(file, [...args], { timeout: timeoutMs }, (err) => {
+        if (!err) return resolve(0);
+        // A number is the exit code of a command that ran. Anything else (ENOENT, a timeout
+        // that killed it) is "it did not answer".
+        const code = (err as { code?: unknown }).code;
+        resolve(typeof code === 'number' && !(err as { killed?: boolean }).killed ? code : null);
+      });
+    } catch {
+      resolve(null);
+    }
+  });
+}
+
+async function check(deps: DeveloperToolsDeps): Promise<LocalModelDeveloperTools> {
+  if (deps.platform !== 'darwin') return 'unknown';
+  let code: number | null;
+  try {
+    code = await deps.run(XCODE_SELECT, ['-p'], DEVELOPER_TOOLS_TIMEOUT_MS);
+  } catch {
+    code = null;
+  }
+  if (code === null || !Number.isInteger(code)) return 'unknown';
+  return code === 0 ? 'present' : 'missing';
+}
+
+/**
+ * A check that remembers its answer for a minute and shares one run among callers that ask at
+ * the same time. `now` is the clock of the cache; a test injects its own.
+ */
+export function createDeveloperToolsCheck(
+  deps: Partial<DeveloperToolsDeps> & { now?: () => number } = {}
+): () => Promise<LocalModelDeveloperTools> {
+  const resolved: DeveloperToolsDeps = {
+    platform: deps.platform ?? process.platform,
+    run: deps.run ?? runBounded,
+  };
+  const now = deps.now ?? Date.now;
+  let cached: { answer: LocalModelDeveloperTools; at: number } | undefined;
+  let inFlight: Promise<LocalModelDeveloperTools> | undefined;
+  return () => {
+    if (cached && now() - cached.at < DEVELOPER_TOOLS_CACHE_MS) return Promise.resolve(cached.answer);
+    inFlight ??= check(resolved)
+      .then((answer) => {
+        if (answer !== 'unknown') cached = { answer, at: now() };
+        return answer;
+      })
+      .finally(() => {
+        inFlight = undefined;
+      });
+    return inFlight;
+  };
+}
+
+/** The check of this server's own Mac. */
+let shared = createDeveloperToolsCheck();
+
+/** Forgets the cached answer of this server's own Mac. For tests. */
+export function resetDeveloperToolsCache(): void {
+  shared = createDeveloperToolsCheck();
+}
+
+/**
+ * `present` when `/usr/bin/xcode-select -p` exits 0, `missing` when it exits with anything
+ * else, `unknown` otherwise. Without `deps` it is the cached check of this server's Mac; with
+ * a platform or a runner of the caller's it asks once and remembers nothing.
+ */
 export async function checkDeveloperTools(deps: Partial<DeveloperToolsDeps> = {}): Promise<LocalModelDeveloperTools> {
-  return notImplemented('checkDeveloperTools', deps);
+  if (deps.platform !== undefined || deps.run !== undefined) {
+    return check({ platform: deps.platform ?? process.platform, run: deps.run ?? runBounded });
+  }
+  return shared();
 }

src/local-model/ollama-client.ts

@@ -2,9 +2,6 @@
  * @fileoverview The HTTP client of the model runtime: what Codeman asks its own runtime on
  * the loopback port, and the pure functions that read the answers.
  *
- * CONTRACT STAGE: every function below has its final signature and a body that throws; the
- * bodies are written next.
- *
  * What it asks:
  *  - `GET /api/version`, `GET /api/tags`, `GET /api/ps`, `GET /v1/models`, `DELETE /api/delete`.
  *  - `POST /api/pull` with `stream: true`. The answer is one JSON object per line, and a
@@ -23,24 +20,46 @@
  * Rules:
  *  - Nothing here throws for something a runtime can answer: every outcome is a result with
  *    the job's error code. An abort signal is the result `cancelled`.
+ *  - Every request is bounded: a listing by seconds, the two probes by minutes (the first
+ *    chat loads the model). Only the pull has no deadline of its own, because its length is
+ *    the download; it ends with the stream, and the caller's signal cancels it.
  *  - The runtime does not enforce the context length (a prompt of 167,012 tokens was accepted
  *    at 131072), so nothing here relies on it to.
  *  - Every function takes its `fetch` from the target, so a test passes the fake runtime's
- *    address and spawns nothing.
+ *    address and spawns nothing. The target is always a loopback address the caller built from
+ *    the stored port: no function here takes a URL from a file or a request.
  */
 
 import type { LocalModelErrorCode } from '../types.js';
 
-/** Marks a body the contract stage left unwritten. */
-function notImplemented(what: string, ..._args: unknown[]): never {
-  throw new Error(`${what} is not implemented yet`);
-}
-
 /** How often a pull that ended on an error line or a cut stream is started again. */
 export const PULL_RETRIES = 5;
 /** `max_tokens` of the tool probe. */
 export const TOOL_PROBE_MAX_TOKENS = 1024;
 
+/** How long `/api/version` may take: it is asked while a runtime starts, many times. */
+const VERSION_TIMEOUT_MS = 2_000;
+/** How long a listing or a delete may take. */
+const LIST_TIMEOUT_MS = 10_000;
+/** How long the chat that loads the model may take. A 23 GB model loaded in 5.9 s on the test Mac; a cold disk is slower. */
+const CHAT_PROBE_TIMEOUT_MS = 180_000;
+/** How long the tool probe may take. The model is loaded by then. */
+const TOOL_PROBE_TIMEOUT_MS = 120_000;
+/** `max_tokens` of the chat that loads the model: its answer is not read. */
+const CHAT_PROBE_MAX_TOKENS = 16;
+/** The least time between two progress reports of a pull. */
+const PULL_PROGRESS_INTERVAL_MS = 250;
+/** The window the download speed is averaged over. */
+const PULL_SPEED_WINDOW_MS = 5_000;
+/** The first wait before a pull is started again; it doubles with every retry. */
+const PULL_RETRY_DELAY_MS = 1_000;
+/** A pull line longer than this is not a pull line. It is dropped, so a stream without line breaks cannot grow the buffer. */
+const MAX_PULL_LINE_CHARS = 1024 * 1024;
+/** More layers than any model has. Lines for further ones are counted and not added up, so the layer table cannot grow without bound. */
+const MAX_PULL_LAYERS = 1024;
+/** How much of a runtime's error text is kept as `detail`. */
+const MAX_DETAIL_CHARS = 400;
+
 /** Which runtime to ask. */
 export interface OllamaTarget {
   /** `http://127.0.0.1:<port>`, without a trailing slash. */
@@ -49,6 +68,100 @@ export interface OllamaTarget {
   fetch?: typeof fetch;
 }
 
+// ---------- Plumbing ----------
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value);
+}
+
+function asString(value: unknown): string | undefined {
+  return typeof value === 'string' && value !== '' ? value : undefined;
+}
+
+/** A byte count or a token count as the runtime reports it: a finite number that is not negative. */
+function asCount(value: unknown): number | undefined {
+  return typeof value === 'number' && Number.isFinite(value) && value >= 0 ? value : undefined;
+}
+
+function clip(text: string): string {
+  const trimmed = text.trim();
+  return trimmed.length > MAX_DETAIL_CHARS ? `${trimmed.slice(0, MAX_DETAIL_CHARS)}...` : trimmed;
+}
+
+function errorText(err: unknown): string {
+  if (err instanceof Error) {
+    // undici wraps the reason ("fetch failed") and keeps the useful part in `cause`.
+    const cause = (err as { cause?: unknown }).cause;
+    return clip(cause instanceof Error && cause.message ? `${err.message}: ${cause.message}` : err.message);
+  }
+  return clip(String(err));
+}
+
+/** The error text of a runtime answer: `{"error":"..."}` (its own routes) or `{"error":{"message":"..."}}` (the OpenAI routes). */
+function errorOfBody(body: unknown): string | undefined {
+  if (!isRecord(body)) return undefined;
+  const { error } = body;
+  if (typeof error === 'string') return asString(error);
+  if (isRecord(error)) return asString(error.message);
+  return undefined;
+}
+
+/** The caller's signal joined with a deadline. */
+function bounded(signal: AbortSignal | undefined, timeoutMs: number): AbortSignal {
+  const deadline = AbortSignal.timeout(timeoutMs);
+  return signal ? AbortSignal.any([signal, deadline]) : deadline;
+}
+
+/** An answer of the runtime: its status and its body as JSON (`undefined` when it is not JSON). */
+interface Answer {
+  status: number;
+  body: unknown;
+  text: string;
+}
+
+/**
+ * One bounded request. `undefined` when nothing answered (refused, timed out, aborted): the
+ * caller looks at its own signal to tell an abort from the rest.
+ */
+async function ask(
+  target: OllamaTarget,
+  path: string,
+  init: { method?: string; json?: unknown },
+  timeoutMs: number,
+  signal?: AbortSignal
+): Promise<Answer | undefined> {
+  const fetchFn = target.fetch ?? fetch;
+  try {
+    const res = await fetchFn(`${target.baseUrl}${path}`, {
+      method: init.method ?? 'GET',
+      ...(init.json !== undefined
+        ? { headers: { 'content-type': 'application/json' }, body: JSON.stringify(init.json) }
+        : {}),
+      signal: bounded(signal, timeoutMs),
+    });
+    const text = await res.text();
+    let body: unknown;
+    try {
+      body = text === '' ? undefined : JSON.parse(text);
+    } catch {
+      body = undefined;
+    }
+    return { status: res.status, body, text };
+  } catch {
+    return undefined;
+  }
+}
+
+/** A digest as it is stored and compared: lowercase hex without the `sha256:` prefix. */
+function normalizeDigest(value: unknown): string {
+  return typeof value === 'string'
+    ? value
+        .trim()
+        .toLowerCase()
+        .replace(/^sha256:/, '')
+    : '';
+}
+
 // ---------- Listings ----------
 
 /** One model of `GET /api/tags`: what is on disk. */
@@ -79,24 +192,69 @@ export interface OllamaPsModel {
   digest?: string;
 }
 
+/** The `models` array of a listing, or an empty one. */
+function modelsOf(answer: Answer | undefined): Record<string, unknown>[] {
+  if (!answer || answer.status !== 200 || !isRecord(answer.body)) return [];
+  const { models } = answer.body;
+  return Array.isArray(models) ? models.filter(isRecord) : [];
+}
+
 /** The runtime's version ('0.40.15'), or `undefined` when nothing answers there or the answer is not a runtime's. */
 export async function getRuntimeVersion(target: OllamaTarget, signal?: AbortSignal): Promise<string | undefined> {
-  return notImplemented('getRuntimeVersion', target, signal);
+  const answer = await ask(target, '/api/version', {}, VERSION_TIMEOUT_MS, signal);
+  if (!answer || answer.status !== 200 || !isRecord(answer.body)) return undefined;
+  return asString(answer.body.version);
 }
 
 /** The models on disk. An empty list when the runtime has none or does not answer. */
 export async function listTags(target: OllamaTarget, signal?: AbortSignal): Promise<OllamaTagModel[]> {
-  return notImplemented('listTags', target, signal);
+  const listed: OllamaTagModel[] = [];
+  for (const row of modelsOf(await ask(target, '/api/tags', {}, LIST_TIMEOUT_MS, signal))) {
+    const name = asString(row.name) ?? asString(row.model);
+    if (!name) continue;
+    const details = isRecord(row.details) ? row.details : {};
+    const format = asString(details.format);
+    const runner = asString(details.runner) ?? asString(row.runner);
+    const capabilities = Array.isArray(row.capabilities)
+      ? row.capabilities.filter((entry): entry is string => typeof entry === 'string')
+      : undefined;
+    listed.push({
+      name,
+      size: asCount(row.size) ?? 0,
+      digest: normalizeDigest(row.digest),
+      ...(format ? { format } : {}),
+      ...(runner ? { runner } : {}),
+      ...(capabilities ? { capabilities } : {}),
+    });
+  }
+  return listed;
 }
 
 /** The models loaded right now. An empty list when none is or the runtime does not answer. */
 export async function listRunning(target: OllamaTarget, signal?: AbortSignal): Promise<OllamaPsModel[]> {
-  return notImplemented('listRunning', target, signal);
+  const listed: OllamaPsModel[] = [];
+  for (const row of modelsOf(await ask(target, '/api/ps', {}, LIST_TIMEOUT_MS, signal))) {
+    const name = asString(row.name) ?? asString(row.model);
+    if (!name) continue;
+    const digest = normalizeDigest(row.digest);
+    listed.push({
+      name,
+      size: asCount(row.size) ?? 0,
+      sizeVram: asCount(row.size_vram) ?? 0,
+      contextLength: asCount(row.context_length) ?? 0,
+      ...(digest ? { digest } : {}),
+    });
+  }
+  return listed;
 }
 
 /** The model ids `GET /v1/models` lists, exactly as listed (the runtime answers `data: null` for none). */
 export async function listOpenAiModels(target: OllamaTarget, signal?: AbortSignal): Promise<string[]> {
-  return notImplemented('listOpenAiModels', target, signal);
+  const answer = await ask(target, '/v1/models', {}, LIST_TIMEOUT_MS, signal);
+  if (!answer || answer.status !== 200 || !isRecord(answer.body)) return [];
+  const { data } = answer.body;
+  if (!Array.isArray(data)) return [];
+  return data.flatMap((row) => (isRecord(row) && typeof row.id === 'string' && row.id !== '' ? [row.id] : []));
 }
 
 /** The digest `GET /api/tags` reports for `modelId`, or `undefined` when the model is not on disk. */
@@ -105,12 +263,21 @@ export async function readModelDigest(
   modelId: string,
   signal?: AbortSignal
 ): Promise<string | undefined> {
-  return notImplemented('readModelDigest', target, modelId, signal);
+  const found = (await listTags(target, signal)).find((model) => model.name === modelId);
+  return found && found.digest !== '' ? found.digest : undefined;
 }
 
 /** Deletes a model from the runtime's store. True when it is gone afterwards (also when it never was there). */
 export async function deleteModel(target: OllamaTarget, modelId: string, signal?: AbortSignal): Promise<boolean> {
-  return notImplemented('deleteModel', target, modelId, signal);
+  const answer = await ask(
+    target,
+    '/api/delete',
+    { method: 'DELETE', json: { model: modelId } },
+    LIST_TIMEOUT_MS,
+    signal
+  );
+  // 404 is the runtime's answer for a model it does not have.
+  return answer !== undefined && (answer.status === 200 || answer.status === 404);
 }
 
 // ---------- Pull ----------
@@ -154,10 +321,104 @@ export interface PullParser {
  *    `{"status":"writing manifest"}`, `{"status":"success"}`
  *  - `{"error":"max retries exceeded: local error: tls: bad record MAC"}`
  *
- * A line that is not JSON is skipped and still counted.
+ * A line that is not JSON is skipped and still counted. A blank line is not a line.
  */
 export function createPullParser(): PullParser {
-  return notImplemented('createPullParser');
+  const decoder = new TextDecoder();
+  // One entry per layer: what the layer's last line said. A model has a handful of layers.
+  const layers = new Map<string, { total: number; completed: number }>();
+  let pending = '';
+  // True while a line longer than the limit is being skipped up to its line break.
+  let skipping = false;
+  let status: string | undefined;
+  let succeeded = false;
+  let error: string | undefined;
+  let lines = 0;
+
+  function line(text: string): void {
+    const trimmed = text.trim();
+    if (trimmed === '') return;
+    lines += 1;
+    let parsed: unknown;
+    try {
+      parsed = JSON.parse(trimmed);
+    } catch {
+      return;
+    }
+    if (!isRecord(parsed)) return;
+    const failure = errorOfBody(parsed);
+    if (failure !== undefined) {
+      error ??= clip(failure);
+      return;
+    }
+    const lineStatus = asString(parsed.status);
+    if (lineStatus !== undefined) {
+      status = lineStatus;
+      if (lineStatus === 'success') succeeded = true;
+    }
+    const total = asCount(parsed.total);
+    if (total === undefined) return;
+    // A layer is named by its digest; a line without one by its status text.
+    const key = asString(parsed.digest) ?? lineStatus;
+    if (key === undefined) return;
+    const known = layers.get(key);
+    if (!known && layers.size >= MAX_PULL_LAYERS) return;
+    // `completed` is absent until the layer's first bytes arrived: what was seen before stays.
+    const completed = asCount(parsed.completed) ?? known?.completed ?? 0;
+    layers.set(key, { total, completed: Math.min(completed, total) });
+  }
+
+  function feed(text: string): void {
+    let rest = text;
+    for (;;) {
+      const breakAt = rest.indexOf('\n');
+      if (breakAt < 0) break;
+      const head = rest.slice(0, breakAt);
+      rest = rest.slice(breakAt + 1);
+      if (skipping) {
+        // The end of the line that was too long: it was counted when it was dropped.
+        skipping = false;
+      } else {
+        line(pending + head);
+      }
+      pending = '';
+    }
+    if (skipping) return;
+    pending += rest;
+    if (pending.length > MAX_PULL_LINE_CHARS) {
+      pending = '';
+      skipping = true;
+      lines += 1;
+    }
+  }
+
+  return {
+    push(chunk) {
+      feed(typeof chunk === 'string' ? chunk : decoder.decode(chunk, { stream: true }));
+    },
+    end() {
+      feed(decoder.decode());
+      if (!skipping && pending !== '') line(pending);
+      pending = '';
+      skipping = false;
+    },
+    snapshot() {
+      let completedBytes = 0;
+      let totalBytes = 0;
+      for (const layer of layers.values()) {
+        completedBytes += layer.completed;
+        totalBytes += layer.total;
+      }
+      return {
+        completedBytes,
+        totalBytes,
+        ...(status !== undefined ? { status } : {}),
+        succeeded,
+        ...(error !== undefined ? { error } : {}),
+        lines,
+      };
+    },
+  };
 }
 
 /** How far a pull is, for the caller's progress display. */
@@ -196,9 +457,145 @@ export type PullResult =
     }
   | { ok: false; code: 'cancelled' };
 
+/** How one request of a pull ended. */
+type PullAttempt =
+  | { kind: 'success'; totalBytes: number }
+  | { kind: 'cancelled' }
+  | { kind: 'fatal'; code: 'model-not-found' | 'disk-full'; detail: string }
+  | { kind: 'retry'; detail: string };
+
+/**
+ * What an error text of the runtime means for the pull. A model the registry does not have and
+ * a full disk do not get better by asking again; everything else (a damaged download, a
+ * dropped connection) may.
+ */
+function classifyPullError(text: string): PullAttempt {
+  const detail = clip(text);
+  if (/file does not exist|manifest unknown|manifest\b.*\bnot found|model\b.*\bnot found/i.test(text)) {
+    return { kind: 'fatal', code: 'model-not-found', detail };
+  }
+  if (/no space left on device|disk (is )?full|not enough (free )?(disk )?space/i.test(text)) {
+    return { kind: 'fatal', code: 'disk-full', detail };
+  }
+  return { kind: 'retry', detail };
+}
+
+/** A wait that ends early when the signal aborts. */
+function waitFor(ms: number, signal?: AbortSignal): Promise<void> {
+  return new Promise((resolve) => {
+    if (signal?.aborted) return resolve();
+    const done = (): void => {
+      clearTimeout(timer);
+      signal?.removeEventListener('abort', done);
+      resolve();
+    };
+    const timer = setTimeout(done, ms);
+    signal?.addEventListener('abort', done, { once: true });
+  });
+}
+
+/** One `POST /api/pull`, read to its end. */
+async function pullOnce(target: OllamaTarget, modelId: string, options: PullOptions): Promise<PullAttempt> {
+  const { signal, onProgress } = options;
+  const now = options.now ?? Date.now;
+  const fetchFn = target.fetch ?? fetch;
+  let res: Response;
+  try {
+    res = await fetchFn(`${target.baseUrl}/api/pull`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({ model: modelId, stream: true }),
+      ...(signal ? { signal } : {}),
+    });
+  } catch (err) {
+    return signal?.aborted ? { kind: 'cancelled' } : { kind: 'retry', detail: errorText(err) };
+  }
+
+  const parser = createPullParser();
+  // The speed is the bytes of the last few seconds: (when, how far) pairs, the oldest first.
+  const samples: { at: number; completed: number }[] = [];
+  let lastReport = Number.NEGATIVE_INFINITY;
+  const report = (force: boolean): void => {
+    if (!onProgress) return;
+    const at = now();
+    if (!force && at - lastReport < PULL_PROGRESS_INTERVAL_MS) return;
+    const snap = parser.snapshot();
+    // Before the first layer line there is no size to show.
+    if (snap.totalBytes <= 0) return;
+    lastReport = at;
+    samples.push({ at, completed: snap.completedBytes });
+    while (samples.length > 2 && at - samples[1].at >= PULL_SPEED_WINDOW_MS) samples.shift();
+    const first = samples[0];
+    const seconds = (at - first.at) / 1000;
+    const moved = snap.completedBytes - first.completed;
+    try {
+      onProgress({
+        completedBytes: snap.completedBytes,
+        totalBytes: snap.totalBytes,
+        ...(seconds > 0 && moved >= 0 ? { bytesPerSecond: Math.round(moved / seconds) } : {}),
+      });
+    } catch {
+      // A display that fails must not fail the download.
+    }
+  };
+
+  let streamError: string | undefined;
+  try {
+    if (res.body) {
+      for await (const chunk of res.body as unknown as AsyncIterable<Uint8Array>) {
+        parser.push(chunk);
+        report(false);
+      }
+    }
+  } catch (err) {
+    streamError = errorText(err);
+  }
+  // An abort ends the stream with an error too: it is a cancel, not a cut.
+  if (signal?.aborted) return { kind: 'cancelled' };
+  parser.end();
+  const snap = parser.snapshot();
+
+  if (snap.error !== undefined) return classifyPullError(snap.error);
+  if (res.status !== 200) return classifyPullError(`The runtime answered ${res.status} to the pull`);
+  if (!snap.succeeded) {
+    return { kind: 'retry', detail: streamError ?? 'The download ended before the runtime reported success' };
+  }
+  report(true);
+  if (snap.totalBytes > 0) return { kind: 'success', totalBytes: snap.totalBytes };
+  // A pull of a model that was already complete may name no layer. The size is then what the
+  // runtime lists for the model, which is the same figure a full pull reports as its total.
+  const listed = (await listTags(target, signal)).find((model) => model.name === modelId);
+  return { kind: 'success', totalBytes: listed?.size ?? 0 };
+}
+
 /** Pulls `modelId` and waits for the end. Resuming is calling it again. Never throws. */
 export async function pullModel(target: OllamaTarget, modelId: string, options: PullOptions = {}): Promise<PullResult> {
-  return notImplemented('pullModel', target, modelId, options);
+  const { signal } = options;
+  const retries =
+    options.retries !== undefined && Number.isInteger(options.retries) && options.retries >= 0
+      ? options.retries
+      : PULL_RETRIES;
+  const sleep = options.sleep ?? ((ms: number) => waitFor(ms, signal));
+  let lastDetail: string | undefined;
+  for (let attempt = 0; attempt <= retries; attempt++) {
+    if (signal?.aborted) return { ok: false, code: 'cancelled' };
+    if (attempt > 0) {
+      await sleep(PULL_RETRY_DELAY_MS * 2 ** (attempt - 1));
+      if (signal?.aborted) return { ok: false, code: 'cancelled' };
+    }
+    let outcome: PullAttempt;
+    try {
+      outcome = await pullOnce(target, modelId, options);
+    } catch (err) {
+      // Only an injected `fetch` or clock can throw here. It must not end the pull as a crash.
+      outcome = { kind: 'retry', detail: errorText(err) };
+    }
+    if (outcome.kind === 'success') return { ok: true, totalBytes: outcome.totalBytes };
+    if (outcome.kind === 'cancelled') return { ok: false, code: 'cancelled' };
+    if (outcome.kind === 'fatal') return { ok: false, code: outcome.code, detail: outcome.detail };
+    lastDetail = outcome.detail;
+  }
+  return { ok: false, code: 'pull-failed', ...(lastDetail !== undefined ? { detail: lastDetail } : {}) };
 }
 
 // ---------- The check after the pull ----------
@@ -218,12 +615,53 @@ export interface LoadedModel {
 
 /** The body of the tiny chat that loads the model: one short user message, `reasoning_effort: "none"`, a small `max_tokens`. Pure. */
 export function buildChatProbeRequest(modelId: string): Record<string, unknown> {
-  return notImplemented('buildChatProbeRequest', modelId);
+  return {
+    model: modelId,
+    messages: [{ role: 'user', content: 'Reply with the single word: ready' }],
+    reasoning_effort: 'none',
+    max_tokens: CHAT_PROBE_MAX_TOKENS,
+    temperature: 0,
+    stream: false,
+  };
+}
+
+/** A function tool of the tool probe, in the shape `/v1/chat/completions` takes. */
+function probeTool(name: string, description: string, properties: Record<string, string>): Record<string, unknown> {
+  return {
+    type: 'function',
+    function: {
+      name,
+      description,
+      parameters: {
+        type: 'object',
+        properties: Object.fromEntries(
+          Object.entries(properties).map(([key, about]) => [key, { type: 'string', description: about }])
+        ),
+        required: Object.keys(properties),
+      },
+    },
+  };
 }
 
 /** The body of the tool probe: a `tools` array, `reasoning_effort: "none"`, `max_tokens: TOOL_PROBE_MAX_TOKENS`. Pure. */
 export function buildToolProbeRequest(modelId: string): Record<string, unknown> {
-  return notImplemented('buildToolProbeRequest', modelId);
+  return {
+    model: modelId,
+    messages: [
+      { role: 'system', content: 'You are a coding agent. Use the tools you are given to do what the user asks.' },
+      { role: 'user', content: 'Read the file README.md and tell me what it says.' },
+    ],
+    // The three tools a coding agent always has. The task needs the first.
+    tools: [
+      probeTool('read_file', 'Read a file and return its content.', { path: 'The path of the file.' }),
+      probeTool('write_file', 'Write a file.', { path: 'The path of the file.', content: 'The new content.' }),
+      probeTool('run_command', 'Run a shell command and return its output.', { command: 'The command line.' }),
+    ],
+    reasoning_effort: 'none',
+    max_tokens: TOOL_PROBE_MAX_TOKENS,
+    temperature: 0,
+    stream: false,
+  };
 }
 
 /**
@@ -237,13 +675,43 @@ export function judgeLoaded(
   modelId: string,
   context: number
 ): { ok: true; loaded: LoadedModel } | { ok: false; code: VerifyFailureCode; detail?: string } {
-  return notImplemented('judgeLoaded', models, modelId, context);
+  const model = models.find((entry) => entry.name === modelId);
+  if (!model) return { ok: false, code: 'load-failed', detail: 'The runtime does not list the model as loaded' };
+  if (model.size <= 0)
+    return { ok: false, code: 'load-failed', detail: 'The runtime reports no size for the loaded model' };
+  if (model.sizeVram !== model.size) {
+    return {
+      ok: false,
+      code: 'does-not-fit',
+      detail: `${model.sizeVram} of ${model.size} bytes are on the GPU`,
+    };
+  }
+  if (model.contextLength !== context) {
+    return {
+      ok: false,
+      code: 'context-not-applied',
+      detail: `The runtime reports a context of ${model.contextLength} tokens, not ${context}`,
+    };
+  }
+  return { ok: true, loaded: { context: model.contextLength, sizeBytes: model.size, sizeVramBytes: model.sizeVram } };
+}
+
+/** Whether the arguments of a tool call are a JSON object: as text that parses to one, or already as one. */
+function argumentsAreObject(value: unknown): boolean {
+  if (isRecord(value)) return true;
+  if (typeof value !== 'string') return false;
+  try {
+    return isRecord(JSON.parse(value));
+  } catch {
+    return false;
+  }
 }
 
 /**
  * Judges the answer of the tool probe. Pure. `status` is the HTTP status, `body` the parsed
  * JSON (or `undefined` when it did not parse).
- *  - a tool call whose `arguments` parse as a JSON object: passed;
+ *  - a tool call whose `arguments` parse as a JSON object: passed (when the answer holds
+ *    several calls, every one must have a name and such arguments);
  *  - `finish_reason` is `length`: `probe-unfinished` (the token limit ended it, so it proves nothing);
  *  - any other answer of status 200: `no-tool-call`;
  *  - another status: `load-failed`.
@@ -252,7 +720,33 @@ export function judgeToolProbe(
   status: number,
   body: unknown
 ): { ok: true } | { ok: false; code: VerifyFailureCode; detail?: string } {
-  return notImplemented('judgeToolProbe', status, body);
+  if (status !== 200) {
+    const said = errorOfBody(body);
+    return { ok: false, code: 'load-failed', detail: clip(said ?? `The runtime answered ${status}`) };
+  }
+  const choice = isRecord(body) && Array.isArray(body.choices) ? body.choices[0] : undefined;
+  const message = isRecord(choice) && isRecord(choice.message) ? choice.message : undefined;
+  const calls = message && Array.isArray(message.tool_calls) ? message.tool_calls : [];
+  if (calls.length > 0) {
+    const wellFormed = calls.every(
+      (call) =>
+        isRecord(call) &&
+        isRecord(call.function) &&
+        asString(call.function.name) !== undefined &&
+        argumentsAreObject(call.function.arguments)
+    );
+    if (wellFormed) return { ok: true };
+    return { ok: false, code: 'no-tool-call', detail: 'The model called a tool with arguments that are not JSON' };
+  }
+  if (isRecord(choice) && choice.finish_reason === 'length') {
+    return { ok: false, code: 'probe-unfinished', detail: `The answer ended at ${TOOL_PROBE_MAX_TOKENS} tokens` };
+  }
+  const said = message ? asString(message.content) : undefined;
+  return {
+    ok: false,
+    code: 'no-tool-call',
+    detail: said ? clip(`The model answered in text: ${said}`) : 'The answer holds no tool call',
+  };
 }
 
 /** How the check ended. */
@@ -271,5 +765,44 @@ export async function verifyModel(
   context: number,
   signal?: AbortSignal
 ): Promise<VerifyResult> {
-  return notImplemented('verifyModel', target, modelId, context, signal);
+  const cancelled: VerifyResult = { ok: false, code: 'cancelled' };
+  if (signal?.aborted) return cancelled;
+
+  // 1. The chat that loads the model. Its text is not read: only that it was answered.
+  const chat = await ask(
+    target,
+    '/v1/chat/completions',
+    { method: 'POST', json: buildChatProbeRequest(modelId) },
+    CHAT_PROBE_TIMEOUT_MS,
+    signal
+  );
+  if (signal?.aborted) return cancelled;
+  if (!chat) return { ok: false, code: 'load-failed', detail: 'The runtime did not answer the first request' };
+  if (chat.status !== 200) {
+    return {
+      ok: false,
+      code: 'load-failed',
+      detail: clip(errorOfBody(chat.body) ?? `The runtime answered ${chat.status}`),
+    };
+  }
+
+  // 2. What the runtime says it loaded.
+  const judged = judgeLoaded(await listRunning(target, signal), modelId, context);
+  if (signal?.aborted) return cancelled;
+  if (!judged.ok) return judged;
+
+  // 3. One tool call.
+  const probe = await ask(
+    target,
+    '/v1/chat/completions',
+    { method: 'POST', json: buildToolProbeRequest(modelId) },
+    TOOL_PROBE_TIMEOUT_MS,
+    signal
+  );
+  if (signal?.aborted) return cancelled;
+  if (!probe)
+    return { ok: false, code: 'probe-unfinished', detail: 'The runtime did not answer the tool request in time' };
+  const tool = judgeToolProbe(probe.status, probe.body);
+  if (!tool.ok) return tool;
+  return { ok: true, loaded: judged.loaded };
 }