 Kyle Carberry
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ddfe630757
|
refactor(chatd): replace fantasy.Agent with custom agent loop (#22507)
## Summary
Replaces fantasy's `Agent` abstraction with a direct step loop calling
`LanguageModel.Stream()`. Fantasy is retained as the provider
abstraction layer (streaming parsers, types, tool schema) but we no
longer use `fantasy.Agent`, `AgentStreamCall`, `AgentResult`, or
`StepResult`.
## Problems solved
| Problem | Before | After |
|---|---|---|
| **Sentinel prompt hack** | fantasy.Agent requires non-empty Prompt →
UUID sentinel generated and stripped in PrepareStep | Messages passed
directly to `model.Stream()` |
| **Discarded PersistStep errors** | `_ = opts.OnStepFinish(result)`
silently swallows errors | Errors propagate directly from
`PersistStep()` |
| **Shadow draft state** | ~160 LOC tracking content in parallel because
fantasy doesn't expose in-progress content on interruption |
`stepResult` owns content directly; `flushActiveState()` is trivial |
| **Nested retry layers** | fantasy's 2-attempt retry nested inside
chatretry's indefinite retry | Single `chatretry.Retry` layer |
| **Callback-mediated compaction** | Mutex + boolean flag + coordination
between OnStepFinish/PrepareStep callbacks | Inline `if` statement
between steps |
| **Duplicate compaction paths** | `compactStep()` + `maybeCompact()`
sharing ~80% logic | Single `tryCompact()` function |
## Changes
### `coderd/chatd/chatloop/chatloop.go` — Rewritten
- **Removed**: `fantasy.NewAgent()`, `AgentStreamCall`, sentinel prompt,
shadow draft state (~160 LOC of closures), `compactedMu`/`compacted`
flag, `PrepareStepResult`
- **Added**: `stepResult` struct, `processStepStream()` (stream
consumer), `executeTools()` (sequential tool execution),
`flushActiveState()` (interrupt handling), `buildToolDefinitions()`,
`toResponseMessages()`
- **Changed**: `Run()` return type from `(*fantasy.AgentResult, error)`
to `error` (callers already discarded the result)
- **Preserved**: Anthropic prompt caching, reasoning title extraction,
`extractContextLimit()`, `ErrInterrupted` semantics
### `coderd/chatd/chatloop/compaction.go` — Simplified
- Merged `compactStep()` + `maybeCompact()` → single `tryCompact()`
- Removed `[]StepResult` parameter from `generateCompactionSummary()`
(caller provides complete message list)
- Kept helper functions: `normalizedCompactionConfig`,
`contextTokensFromUsage`, `resolveContextLimit`, `shouldCompact`
### `coderd/chatd/chatd.go` — Caller updates
- Removed `AgentStreamCall` construction
- Changed `_, err = chatloop.Run(...)` to `err = chatloop.Run(...)`
- Model parameters moved from `AgentStreamCall` fields to `RunOptions`
fields
### Tests — 4 new tests
- `MidLoopCompactionReloadsMessages` — compaction fires mid-loop,
messages reloaded
- `PostRunCompactionSkippedAfterMidLoop` — no double compaction
- `MultiStepToolExecution` — tools execute between steps, results feed
next step
- `PersistStepErrorPropagates` — persistence errors propagate (was
silently discarded)
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2026-03-02 18:51:57 -05:00 |
|
|
Kyle Carberry
|
edee917d88
|
feat: add experimental agents support (#22290)
feat: add AI chat system with agent tools and chat UI
Introduce the chatd subsystem and Agents UI for AI-powered chat
within Coder workspaces.
- Add chatd package with chat loop, message compaction, prompt
management, and LLM provider integration (OpenAI, Anthropic)
- Add agent tools: create workspace, list/read templates, read/write/
edit files, execute commands
- Add chat API endpoints with streaming, message editing, and
durable reconnection
- Add database schema and migrations for chats, chat messages, chat
providers, and chat model configs
- Add RBAC policies and dbauthz enforcement for chat resources
- Add Agents UI pages with conversation timeline, queued messages
list, diff viewer, and model configuration panel
- Add comprehensive test coverage including coderd integration tests,
chatd unit tests, and Storybook stories
- Gate feature behind experiments flag
---------
Co-authored-by: Cian Johnston <cian@coder.com>
Co-authored-by: Danielle Maywood <danielle@themaywoods.com>
Co-authored-by: Jeremy Ruppel <jeremy@coder.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
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2026-02-27 16:50:56 +00:00 |
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