[Bug]: OpenCode CLI OSC title leak pollutes agent inventory — Agent not found → UnknownError

Bug

OpenCode <=1.18 writes OSC title sequence ESC ]0;<cwd>: ready BEL to stdout for every non-help command even when stdout is a pipe. T3 captures that via ChildProcessSpawner + collectStreamAsString and the parsers stored a polluted agent id:

Agent not found: "\u001b]0;imbios: ready\u0007build". Available agents: build, explore, general, plan

Followed by generic wrapper:

UnknownError: UnknownError
    at <anonymous> (//root/chunk-09733s3k.js:1096:2069)
    at SessionPrompt.createUserMessage (//root/chunk-09733s3k.js:1096:9954)
    ...
    at SessionHttpApi.promptAsync (//root/chunk-ys5kjase.js:2:84381)

Evidence

~/.t3/userdata/logs/provider/events.*.log shows two session.error per turn: first is the polluted agent, second is the generic UnknownError.
projection_threads.model_selection_json polluted for 3 threads:

{"instanceId":"opencode","model":"opencode-go/mimo-v2.5","options":[{"id":"agent","value":"\u001b]0;imbios: ready\u0007build"}]}

Repro: opencode agent list 2>&1 | cat -v → ^[]0;tmp: ready^Gbuild (primary) even with env -i PATH=... opencode agent list and TERM=dumb — opencode binary itself leaks, not shell/ghostty.
Also opencode models --verbose 2>&1 | cat -v → ^[]0;tmp: ready^Gopencode/big-pickle — caused model inventory to drop to 0 without the fix (SLUG_RE didn't match). Skills JSON degraded to [].

Root cause

apps/server/src/provider/opencodeRuntime.ts:208,270 parseModelsCliOutput/parseAgentListCliOutput assumed clean stdout. No strip of OSC ESC ]...BEL / CSI ESC[...m.

Fix

See PR from fork (ImBIOS#2 merged to ImBIOS:main, will open upstream PR). Summary:

packages/shared/src/stripTerminalEscapes.ts: shared stripTerminalEscapes/sanitizeTerminalValue
opencodeRuntime.ts: strip before parseModels/Agent/Skills, defensive at entry
OpenCodeProvider.ts: sanitize inventory agent names/variants + --version parsing
OpenCodeAdapter.ts + OpenCodeTextGeneration.ts: sanitize stored agent/variant before session.promptAsync
packages/shared/src/model.ts: sanitize persisted option values and model slugs on read (repairs polluted threads without DB migration)
Tests: regression cases for OSC/ANSI in both parsers

Upstream

Should be fixed in sst/opencode as well: CLI should write OSC title to /dev/tty/stderr only when isTTY, not stdout pipe. T3 fix is defensive regardless.

Repro steps

opencode agent list | cat -v shows OSC prefix
Start T3 server, no external opencode server → loadInventoryFromCli stores polluted agent
New thread → send → fails with UnknownError stack

Expected

Clean agent inventory, no OSC leak.

📦 Want this fix today — without waiting for #7755 to merge?

Two ways, both live now:

Option A — zero tooling: ImBIOS/t3code@main already contains this fix (landed via ImBIOS#2). Clone/vendor from there:

gh repo clone ImBIOS/t3code && cd t3code && bun test

Option B — forkhub intent-patch (recommended if you maintain your own fork and want to keep receiving upstream releases)

This fix is published as an intent-patch: instead of pinning a frozen diff, you import the spec (INTENT.md + acceptance criteria + verify.sh), and an AI coding agent re-derives it against whatever upstream SHA your checkout is at — then again on every future upstream release, until #7755 merges (after which fh cleanup --apply drops the patch and you return to official releases).

# 1) Install the CLI (canary channel)
pnpm add -g "github:ImBIOS/forkhub#canary&path:packages/cli"

# 2) From inside YOUR t3code checkout
#    (remotes: upstream = pingdotgg/t3code, origin = <you>/t3code)
fh init --target github.com/pingdotgg/t3code

# 3) Import this patch intent (author attribution preserved)
fh import https://github.com/ImBIOS/.forkhub/blob/main/repos/github.com/pingdotgg/t3code/patches/fix-t3code-strip-osc-ansi-escapes-from-opencode-cl-y7shx01y/INTENT.md

# 4) Re-derive against your checkout
fh re-derive fix-t3code-strip-osc-ansi-escapes-from-opencode-cl-y7shx01y
#    → prints a context-bundle path (README.md inside is authoritative)

# 5) Have your AI agent implement the bundle (OpenCode: run the `/forkhub`
#    skill with no args), writing REALIZATION/realization.diff, then:
fh apply <bundle-path>          # verify gate runs `bun test`

# 6) Ongoing maintenance
fh watch        # daemon: auto drift-detect → regenerate → apply → tag
fh update       # advance to latest tagged build
fh pr-status    # tracks THIS issue/PR state via gh

Patch contents (browse): INTENT.md (root cause, non-negotiables, implementation notes) · ACCEPTANCE.md · reference.diff (+139/−14, hint only) · verify.sh. Discoverable via fh search --author ImBIOS or fh search --target github.com/pingdotgg/t3code.

If you hit the same bug on a different T3 version, the intent survives: re-derivation adapts the fix to your tree rather than replaying a stale diff.

fix(server): strip OSC/ANSI escapes from OpenCode CLI inventory and s…

fix(server): sanitize model selections on creation and handle truncat…

Related report #7716 covers the same problem and adds useful evidence.

The exact broken build-agent value contains the OSC title fragment ready build. Issue 7754 documents the same stdout escape leak, failed agent selection, and persisted polluted value, with a more complete reproduction. This is not the separate plan-mode filter or custom-agent enumeration issue.

I'm linking the report here before I close it as a duplicate during an automated pass. The source report and its attachments will remain available at #7716.

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[Bug]: OpenCode CLI OSC title leak pollutes agent inventory — Agent not found → UnknownError #7754

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📦 Want this fix today — without waiting for #7755 to merge?

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[Bug]: OpenCode CLI OSC title leak pollutes agent inventory — Agent not found → UnknownError #7754

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ImBIOS commented on Aug 23, 2026

📦 Want this fix today — without waiting for #7755 to merge?

t3dotgg commented on Aug 27, 2026

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