Adds real-time git status watching for workspace agents, so the frontend
can subscribe over WebSocket and show
git file changes in near real-time.
1. Subscription is scoped to a **chat** via `GET
/api/experimental/chats/{chat}/git/watch`.
2. The workspace agent automatically determines which paths to watch
based on tool calls made by the chat (and its ancestor chats).
3. Workspace agent polls subscribed repo working trees on a 30s
interval, on tools calls, and on explicit `refresh` from the client.
4. Scans are rate-limited to at most once per second.
5. Edited paths are tracked **in-memory** inside the workspace agent.
There is no database persistence — state is lost on agent restart. This
will be addresses in a future PR.
6. Messages sent over WebSocket include a full-repo snapshot (unified
diff, branch, origin). A new message is emitted only when the snapshot
changes.
This PR was implemented with AI with me closely controlling what it's
doing. The code follows a plan file that was updated continuously during
implementation. Here's the file if you'd like to see it:
[project.md](https://gist.github.com/hugodutka/8722cf80c92f8a56555f7bc595b770e2).
It reflects the current state of the PR.
## Problem
The `agentproc` process manager spawns processes with only
`os.Environ()`, missing agent-level environment variables like
`GIT_ASKPASS`, `CODER_*`, and `GIT_SSH_COMMAND` that are injected by the
agent's `updateCommandEnv` function. This means processes started
through the HTTP process API (used by chat tools) cannot authenticate
git operations via the Coder gitaskpass helper.
By contrast, SSH sessions get the full agent environment because the SSH
server calls `updateCommandEnv` via its `UpdateEnv` config hook.
## Fix
Wire the agent's `updateCommandEnv` hook into the process manager so all
spawned processes receive the full agent environment. The hook is:
- Passed as a parameter through `NewAPI` → `newManager`
- Called in `manager.start()` with `os.Environ()` as the base, producing
the same enriched env that SSH sessions get
- Gracefully falls back to `os.Environ()` if the hook returns an error
Request-level env vars (`req.Env`, set by chat tools) are still appended
last and take precedence.
## Changes
- `agent/agentproc/process.go`: Add `updateEnv` field to manager, call
it when building process env
- `agent/agentproc/api.go`: Accept `updateEnv` parameter in `NewAPI`
- `agent/agent.go`: Pass `a.updateCommandEnv` when creating the process
API
- `agent/agentproc/api_test.go`: Add `UpdateEnvHook` and
`UpdateEnvHookOverriddenByReqEnv` tests
Co-authored-by: Coder <coder@coder.com>
## Summary
Adds a new agent-side process management HTTP API and rewrites the chat
execute tool to use it instead of SSH sessions.
## What changed
### New agent/agentproc/ package
- **headtail.go** — Thread-safe io.Writer with bounded memory (16KB head
+ 16KB tail ring buffer). Provides LLM-ready output with truncation
metadata and long-line truncation at 2048 bytes.
- **headtail_test.go** — 16 tests including race detector coverage for
concurrent writes.
- **process.go** — Manager + Process types for lifecycle management
using agentexec.Execer for proper OOM/nice scores.
- **api.go** — HTTP API following the agentfiles chi router pattern. 4
endpoints: start, list, output, signal.
### Agent wiring (agent/agent.go, agent/api.go)
Mounts the process API at /api/v0/processes, mirroring how agentfiles is
mounted.
### SDK (codersdk/workspacesdk/agentconn.go)
4 new AgentConn interface methods + 7 request/response types:
- StartProcess, ListProcesses, ProcessOutput, SignalProcess
### Execute tool rewrite (coderd/chatd/chattool/execute.go)
- SSH to Agent API: conn.StartProcess() + conn.ProcessOutput() polling
- New parameters: workdir, run_in_background
- Structured response: success, exit_code, wall_duration_ms, error,
truncated, note, background_process_id
- Non-interactive env vars: GIT_EDITOR=true, TERM=dumb, NO_COLOR=1,
PAGER=cat, etc.
- Output truncation: HeadTailBuffer caps at 32KB for LLM consumption
- File-dump detection with advisory notes suggesting read_file
- Default timeout: 60s to 10s
- Foreground polling: 200ms intervals until exit or timeout
## Architecture
State lives on the agent, surviving coderd failover and instance
changes. Any coderd replica can query any agent via HTTP over tailnet.
- Integrates the `agentexec` pkg into the agent and removes the
legacy system of iterating over the process tree. It adds some linting
rules to hopefully catch future improper uses of `exec.Command` in the package.
- An opt-in feature has been added to the agent to allow
deprioritizing non coder-related processes for CPU by setting their
niceness level to 10.
- Opting in to the feature requires setting CODER_PROC_PRIO_MGMT to a non-empty value.
Kyle Carberry