Codeman/docs/wiki/Working-With-Files.md

Working With Files

Reading, editing, attaching, and previewing files without leaving the dashboard. Useful on a desktop; on a phone it is the difference between reviewing an agent's work and waiting until you get home.

The File Viewer

A panel that browses the active session's working directory. Its header button is on by default; if it is missing, re-enable it in App Settings → Header & Panels.

It renders what it can:

Kind	Behaviour
Text and code	Plain preview with Lines (line numbers) and Wrap toggles in the header. Long files are truncated in plain preview.
Markdown	Rendered by default: headings, tables, code blocks with copy buttons, images and links relative to the file (root-relative ones resolve from the workspace root, as on GitHub). Links to another heading of the same file ([Install](#installation)) scroll to it, with GitHub's heading names (lower-case, punctuation dropped, repeats numbered -1, -2), and never leave the page. Opened from an attachment card, where the file's folder is unknown, relative images show their alt text and relative links show as plain text. The MD pill in the header flips to source.
Images	Inline.
Audio and video	Inline with a working scrub bar, because range requests are supported.
Spreadsheets (.xlsx)	Read-only grid, parsed in your browser (never on the server), up to 10 MB. .xls and .ods are download only.
PDF and Office documents	Converted for preview when a converter is available.
Anything else	Download.

Caps: 10 MB for text preview, 2 GB for raw and download (set CODEMAN_MAX_DOWNLOAD_BYTES to change it, 0 for no limit — these bodies are streamed, so a large file costs a read stream rather than server memory). Sensitive paths (.env, anything matching credentials, ~/.ssh, AWS credentials) are blocked from download, and SVG and HTML are served as downloads rather than rendered, so they cannot execute in the page.

The preview window has Back and Forward buttons (also Alt+← and Alt+→) once you have opened a second file, so a link into another document is no longer one way. Expand fills the screen and is remembered per device, and the corner grip resizes the window. On a phone the window is always full screen, so Expand and the grip are hidden there.

Closing the preview pauses and unloads any playing media. A video that keeps playing after you close the panel means you are on an old version.

Editing in place

Text files can be edited and saved directly in the viewer. Click the pencil in the preview header, edit, Save.

The guardrails are worth knowing, because they are what makes editing safe rather than convenient:

• Extension allowlist, not a blocklist. Code, docs, config, and markup are editable. Anything not on the list is not.
• 512 KB cap on both read and write.
• Edit mode never truncates. The plain preview does truncate long files, and saving a truncated buffer would silently delete the rest, so the editor loads the whole file or refuses.
• Optimistic concurrency. The save carries a hash of what you started from. If the file changed underneath you (likely, when an agent is working in the same repo), the save is rejected rather than clobbering their work.
• No file creation. Writes go to a temporary file and are renamed over the original, and the open never creates. Editing in place is structural, not a rule.
• Line endings are preserved server-side, so editing two lines of a CRLF file does not produce a whole-file diff.
• .git/ is denied outright. Hooks are executable code, and a corrupted index looks unrecoverable to someone who wanted to fix a typo.
• Non-UTF-8 content is refused, verified by a round-trip comparison.

Attachments

Attachments are live references to files outside the session's workspace: a spec on your desktop, a PDF in Downloads, a design document elsewhere on the machine.

Register one from the CLI:

codeman attach /path/to/spec.pdf

An attachment card appears in the session, and the file can be previewed inline. The attachment gets a stable id, and browser requests use that id rather than carrying absolute paths around.

Agents can register attachments too, by emitting a codeman://attach?... link in their output. That path is prompt-injectable by nature, so it is force-confined to the session's workspace: a hostile prompt cannot use it to pull arbitrary host files into the event stream. The gate is an extension allowlist rather than a blocklist.

Document conversion for previews is globally rate limited. Without that, ten large documents detected at once would fork ten multi-minute converter processes.

Clicking a path

File paths in a session are links. That works in two places:

• In the terminal, on any absolute path an agent prints.
• In the response viewer, where paths are usually written as prose or in backticks. They render as underlined monospace links. A Markdown link whose target is a path ([report](/tmp/run/report.json), the way Codex cites files) opens the same way.

Clicking one opens it in the preview: images and PDFs render, video and audio play with a working scrub bar, documents convert, text shows inline, Markdown renders and HTML opens as a page. The exception is a plain text file (a log, .txt, .json, code) inside the workspace clicked in the terminal: that opens in the tail viewer instead, which follows a file that is still being written. A Markdown file always opens rendered, wherever you click it.

Paths outside the session's workspace work too, which matters because that is where most of an agent's output lands: a screenshot in /tmp, a capture in its own scratchpad, a file in another checkout. Those are served through the attachment routes rather than the workspace ones, so the same rules apply as to any other attachment: secret trees are blocked, the extension allowlist decides what can be opened, and symlinks are resolved before either check.

Outside the workspace the allowlist is images, video, audio, PDF, Office documents, and text files, where "text" is the same list the viewer will let you edit: code, config, logs, csv, markdown. The reasoning is that a session can already cat any of those, so the file suffix was never what kept anything secret; the path guard is. Types outside the list (.svg, .bmp) say so rather than failing silently.

An .html file opens as a rendered page by default, with its relative CSS, scripts, images and data files. The page is served from a separate /html-view/... address in a sandbox with no origin of its own, so its scripts can never read Codeman's page, cookies or API.

By the project owner's decision, a rendered page has the same network access as a file you open from disk in your browser. It can load scripts, styles, fonts, images and media from anywhere on the internet (a dashboard that pulls Chart.js from a CDN works), send requests to any host, and read the files in its own folder. It cannot act as Codeman: it has no access to Codeman's page, cookies or API, and no access to any folder other than its own. Since a page can send what it can read to any host, open HTML only from sources you trust, as you would on your own desktop. The Page pill in the viewer header switches to the source view (where Edit works as for any text file), and the viewer falls back to source on its own when a page cannot be rendered: a remote (SSH) case, an HTML file inside a hidden folder, or one sitting directly in a broad folder such as your home folder or /tmp (the page may read the files in its own folder tree, so move it into a folder of its own). The raw file routes still serve HTML as a download only.

Text previews are capped at the first 500 lines, fetched as a partial read, so clicking a one-gigabyte log does not try to paint one.

Log-shaped files inside the workspace still open in the tail viewer, which follows a file as it is written. Outside the workspace they open in the preview instead: the tail viewer runs tail -f, and that is deliberately restricted to the workspace, /var/log and ~/logs.

Nothing is registered until you click. Opening a file this way does not add an attachment card.

Remote (SSH) cases

In a remote case the workspace lives on the other machine, and so do the files. Previews, downloads, text reads and the clicked-path route all go over the same ssh connection the session uses: one realpath plus stat probe for the file and the workspace root, then a streamed cat (or a slice of it, so video seeking works). Symlinks are resolved on the host that can resolve them, the size cap applies to the remote size before a byte is requested, and an unreachable host answers 502 rather than pretending the file is missing. Nothing is ever copied onto the Codeman host, and a same-named local file is never served under a remote name.

Not available over ssh, and said so with a 400 instead of a misleading 404: editing in place, Office previews and generated thumbnails (both need the bytes on the server's disk), the file tree and path picker, and the tail viewer. Docker cases are unaffected, because their workspace is bind-mounted at the same path.

The path picker

For choosing a path rather than typing one. It appears in two places:

• Browse in Add Case → Link Existing.
• The 📁 Path key on the mobile keyboard bar.

It browses one directory at a time and can show hidden entries on request. The current folder is an editable field: type or paste a path and press Enter (or Go) to jump straight there, and a full file path lands in its folder with that file selected. The Sort control orders each listing by name or by modified time (newest first is the quick way to the file an agent just wrote), with folders always ahead of files; the choice is remembered per device. The picker inserts the path into your prompt without pressing Enter, so nothing is submitted by accident. Its sibling ⌫ All key clears the unsent prompt, and never sends the agent's /clear command.

This is a separate file-serving surface from the viewer, with its own rules: it allowlists your home directory, the cases directory, and anything in CODEMAN_FILE_PICKER_ROOTS, and blocks sensitive trees. In multi-user mode a non-admin gets only their own user space as a root, because per-user spaces live inside the home directory and a home-directory root would expose everyone.

Files into a session

Paste from the clipboard or drag and drop straight onto the terminal. The file is written where the agent can read it and the reference is inserted into your prompt. On a phone, the toolbar's Attach button opens the camera, photo library or files, and puts the path on your prompt, where it behaves like text you typed; the Attach button inside the Compose editor does the same into the editor. Dropping a video or a document onto the terminal works the same way.

Images (png, jpg, gif, webp, bmp, heic) are re-encoded on the device before they go up (a GIF goes as is, so it keeps its frames), and HEIC from an iPhone is converted to JPEG. Videos (mp4, webm, mov, m4v, ogv) are stored as recorded, up to 1 GB each by default (CODEMAN_MAX_PASTE_VIDEO_BYTES); they stream to disk rather than through server memory. Documents are the office formats (pdf, docx, pptx, xlsx, zip) and the text family (txt, md, csv, tsv, json, log, yaml, yml, xml). Each is checked on the way in, against its file signature for the binary formats and against its encoding for text (UTF-8, no NUL bytes), so a script renamed to .pdf is refused while a .txt can hold any text at all. A text file in another encoding is refused with a message saying it is not UTF-8 (or that it is UTF-16, which Excel's "Unicode Text" and Notepad's "Unicode" produce); save it as UTF-8 (in Excel, "CSV UTF-8") and attach it again. Files with script or page extensions (sh, py, js, html) are not accepted, since a prompt upload is something for the agent to read, not something for Codeman to store and serve. A document keeps a trimmed copy of its original name, letters, digits, dot, dash and underscore with anything else turned into a dash, so Q3 report.pdf is findable as paste-<time>-<id>-Q3-report.pdf; a name made entirely of other characters saves without one. Uploads are refused for remote (SSH) sessions, whose working directory is on the other host.

Uploads land in .codeman-uploads/ inside the case, next to the code the agent is working on, because that is the one path a local agent and a Docker case (whose workspace is mounted at the same absolute path) both see the same way. The first upload writes a .gitignore of * into .codeman-uploads/, so the directory ignores itself and your repository never picks the files up, while your own ignore file is left alone; a .gitignore you already had there is never overwritten. Files older than seven days are swept hourly, and the directory goes when the last session of the case is closed (a session that is only detached keeps it). Earlier releases wrote to .claude-images/; that directory is still swept and cleaned up the same way for one release so a case in use before the move is not left with stray files.

Generated artifacts

When an agent produces a file the UI can show (a chart, a diagram, a document), it can surface as an artifact attachment rather than a path you have to go and find.

Git changes

Agents often leave work uncommitted or unpushed. Turn on App Settings → Header & Panels → Bottom bar → Git status (per device, off by default) and the right of the bottom bar shows the active session's repository: ● 3 uncommitted files, ↑ 2 commits not pushed, ⚠ merge conflicts, ? 1 a repository git could not read, ✓ when everything is committed and pushed.

Click it for a draggable window, in the style of the File Viewer:

• Uncommitted changes, grouped as staged, not staged, untracked and conflicted, each with a status letter (M modified, A added, D deleted, R renamed, ? new, U conflict).
• Not pushed: the commits no remote has. A branch with no upstream says so, and so does one whose upstream does not exist on the remote, because it was never pushed or was deleted there ("Upstream not on remote"), which counts every commit on no remote rather than showing a green tick.
• Files are grouped under their folders, collapsed until you click a folder (a chain of single-child folders is one row, and the folders you opened stay open when the list refreshes). Turn off App Settings → Header & Panels → Bottom bar → Git status: group files by folder for a flat list of full paths instead.
• Click a file to see what changed in it, as a unified diff with added and removed lines coloured. Staged files show index versus last commit, not-staged files show working tree versus index, untracked files show as all additions and deleted files as all removals. Open file jumps to the File Viewer; Back returns to the list. A binary file shows a note instead, and a diff over 400 KB is cut short.
• A session folder that holds several projects gets one collapsible section per repository found up to two levels down (up to Git status: max repositories, 12 by default; the window says when there are more). A repository git could not read, typically a timeout on a slow network share, is listed with the reason and counted as ? N in the bottom-bar indicator, never silently left out; the git timeout setting raises how long it waits. They all start collapsed (each summary line shows its branch and what is outstanding), and the ones you open stay open when the window refreshes; an unrelated repository above the workspace (a dotfiles repo in your home folder) is ignored.

It is read-only and offline: Codeman never fetches, commits or changes the repository, so "behind" is as of your last fetch. It is not shown for Docker or remote (SSH) sessions, and a repository at or inside a Docker case workspace is skipped even from a local session (a container can write there, and git would run that repository's own configuration on the host). The data comes from GET /api/sessions/:id/git-status and GET /api/sessions/:id/git-diff (see the API reference).

Edit history

The Git panel shows what is different now. The edit history shows what the agent did, one edit at a time, including edits that were later undone or committed. Turn on App Settings → Header & Panels → Header → Edit history (per device, off by default) and a clock button appears in the header next to Attachments. It is not shown on phones.

Click it for a draggable window listing the active session's edits, newest first:

• One row per Edit, Write or MultiEdit, with new for a file the agent created, edit otherwise, and the lines added and removed. Click a row to see that edit's diff inline, coloured like the Git panel; a diff over 64 KB is cut short. Click the path to open the file in the preview.
• Edits made by subagents carry a chip with the subagent's task; hover it for the agent type and its worktree branch. Main agent only hides them. Group by file puts the edits under their file, with the totals on the file's row.
• Images an agent produced with a shell command (a render, a plot, a screenshot) appear as rows with a thumbnail: a .png, .jpg, .gif, .webp or .avif path named in the command or its output counts when the file's modification time falls within that command's run. Images the agent sent you count as well. Click one to open it in the preview.
• Load older reads further back in the conversation.

It works for local Claude sessions only. Remote (SSH), Docker and other CLIs' sessions say so instead.

How it reads:

• Only while you look. The history is read from the session's Claude transcript when you open the window, and again after each edit while it stays open on that session. A closed window reads nothing, and Codeman does no work in the background for sessions nobody looks at.
• The transcript is found through the session's hooks. Each prompt tells Codeman where the session's transcript is. Right after a server restart, before the next prompt, Codeman looks in the session's CLAUDE_CONFIG_DIR if you set one for it in Codeman, else in the default config directory. A CLAUDE_CONFIG_DIR set outside Codeman (in a shell profile or a wrapper script) is only known after the next prompt; until then the window says "No transcript found for this session yet".
• The history is stored, and it holds secrets. Every diff an agent wrote is copied to ~/.codeman/edit-history/<session-id>.json, including API keys or .env contents it edited. The file is readable by your user only, capped at 500 edits and 4 MiB of diff text per session (the oldest are dropped), never part of search, blocked from every file route, and deleted with the session.
• Images go through the existing file routes. A thumbnail inside the workspace uses the File Viewer's route; one outside it is registered like a clicked path (no notification, same file-type allowlist and sensitive-file blocklist). No new route serves a file.

The data comes from GET /api/sessions/:id/edits, GET /api/sessions/:id/edits/:entryId and POST /api/sessions/:id/edits/older (see the API reference).

Gotchas

• The viewer follows the active session's workspace. Switching tabs changes what you are browsing.
• A save can be rejected, and that is the feature. It means the agent edited the file while you were typing. Re-open, re-apply, save again.
• Attachments live outside the workspace on purpose. For files inside it, just use the viewer.
• .env files are readable in the viewer if the extension policy allows the preview, but never downloadable. Do not treat the viewer as a secrets boundary; treat the machine as the boundary.

Read next

• The Dashboard - where the panels live.
• Input And Voice - other ways to get content into a session.
• Security - how the file surfaces are confined.
• docs/file-viewer-edit-plan.md - the edit-mode design.