opencode/packages/opencode/specs/effect/http-api.md

HttpApi migration

Plan for replacing instance Hono route implementations with Effect HttpApi while preserving behavior, OpenAPI, and SDK output during the transition.

End State

• JSON route contracts and handlers live in src/server/routes/instance/httpapi/*.
• Route modules own their HttpApiGroup, schemas, handlers, and route-level middleware.
• httpapi/server.ts only composes groups, instance lookup, observability, and the web handler bridge.
• Hono route implementations are deleted once their HttpApi replacements are default, tested, and represented in the SDK/OpenAPI pipeline.
• Streaming, SSE, and websocket routes move later through Effect HTTP primitives or another explicit replacement plan; they do not need to fit HttpApi if HttpApi is the wrong abstraction.

Current State

• OPENCODE_EXPERIMENTAL_HTTPAPI selects the backend at server startup. Default is still hono.
• server/backend.ts picks one of effect-httpapi or hono; server.ts builds either a pure Effect HttpApi web handler or the legacy Hono app accordingly. The earlier in-Hono "bridge" model has been replaced by this fork-at-startup.
• Legacy Hono routes remain mounted for the hono backend and remain the source for hono-openapi SDK generation.
• An Effect HttpApi OpenAPI surface exists (OpenApi.fromApi(PublicApi) in cli/cmd/generate.ts --httpapi, OPENCODE_SDK_OPENAPI=httpapi in packages/sdk/js/script/build.ts) but is opt-in. The default SDK generation is still Hono.
• httpapi/public.ts carries the Hono-compat normalization for the Effect-generated OpenAPI surface (auth scheme strip, request-body required flag, optional null arms, BadRequestError / NotFoundError remap, $ref self-cycle fix, auth_token query injection). Today's Effect-generated SDK is not byte-identical to the Hono-generated SDK — see Phase 4.
• Auth is centrally configured for the Effect backend via Effect Config (refactor: use Effect config for HttpApi authorization, Fix HttpApi raw route authorization) rather than re-attached in each route module.
• Auth supports Basic auth and the legacy auth_token query parameter through HttpApiSecurity.apiKey.
• Instance context is provided by httpapi/server.ts using directory, workspace, and x-opencode-directory.
• Observability.layer is provided in the Effect route layer and deduplicated through the shared memoMap.
• CORS middleware is wired into both backends (feat(httpapi): add CORS middleware to instance routes).

Migration Rules

• Preserve runtime behavior first. Semantic changes, new error behavior, or route shape changes need separate PRs.
• Migrate one route group, or one coherent subset of a route group, at a time.
• Reuse existing services. Do not re-architect service logic during HTTP boundary migration.
• Effect Schema owns route DTOs. Keep .zod only as compatibility for remaining Hono/OpenAPI surfaces.
• Regenerate the SDK after schema or OpenAPI-affecting changes and verify the diff is expected.
• Do not delete a Hono route until the SDK/OpenAPI pipeline no longer depends on its Hono describeRoute entry.

Route Slice Checklist

Use this checklist for each small HttpApi migration PR:

1. Read the legacy Hono route and copy behavior exactly, including default values, headers, operation IDs, response schemas, and status codes.
2. Put the new HttpApiGroup, route paths, DTO schemas, and handlers in src/server/routes/instance/httpapi/*.
3. Mount the new paths in src/server/routes/instance/index.ts only inside the OPENCODE_EXPERIMENTAL_HTTPAPI block.
4. Use InstanceState.context / InstanceState.directory inside HttpApi handlers instead of Instance.directory, Instance.worktree, or Instance.project ALS globals.
5. Reuse existing services directly. If a service returns plain objects, use Schema.Struct; use Schema.Class only when handlers return actual class instances.
6. Keep legacy Hono routes and .zod compatibility in place for SDK/OpenAPI generation.
7. Add tests that hit the Hono-mounted bridge via InstanceRoutes, not only the raw HttpApi web handler, when the route depends on auth or instance context.
8. Run bun typecheck from packages/opencode, relevant bun run test:ci ... tests from packages/opencode, and ./packages/sdk/js/script/build.ts from the repo root.

Hono Deletion Checklist

Use this checklist before deleting any Hono route implementation. A route being bridged is not enough.

1. HttpApi parity is complete for the route path, method, auth behavior, query parameters, request body, response status, response headers, and error status.
2. The route is mounted by default, not only behind OPENCODE_EXPERIMENTAL_HTTPAPI.
3. If a fallback flag exists, tests cover both the default HttpApi path and the fallback Hono path until the fallback is removed.
4. OpenAPI generation uses the Effect HttpApi route as the source for that path.
5. Generated SDK output is unchanged from the Hono-generated contract, or the SDK diff is intentionally reviewed and accepted.
6. The legacy Hono describeRoute, validator, and handler for that path are removed.
7. Any duplicate Zod-only DTOs are deleted or kept only as .zod compatibility on the canonical Effect Schema.
8. Bridge tests exist for auth, instance selection, success response, and route-specific side effects.
9. Mutation routes prove persisted side effects and cleanup behavior in tests. If the mutation disposes/reloads the active instance, disposal happens through an explicit post-response lifecycle hook rather than inline handler teardown.
10. Streaming, SSE, websocket, and UI bridge routes have a specific non-Hono replacement plan. Do not force them through HttpApi if raw Effect HTTP is a better fit.

Hono can be removed from the instance server only after all mounted Hono route groups meet this checklist and server/routes/instance/index.ts no longer depends on Hono routing for default behavior.

Experimental Read Slice Guidance

For the experimental route group, port read-only JSON routes before mutations:

• Good first batch: GET /console, GET /console/orgs, GET /tool/ids, GET /resource.
• Consider GET /worktree only if the handler uses InstanceState.context instead of Instance.project.
• Defer POST /console/switch, worktree create/remove/reset, and GET /session to separate PRs because they mutate state or have broader pagination/session behavior.
• Preserve response headers such as pagination cursors if a route is ported.
• If SDK generation changes, explain whether it is a semantic contract change or a generator-equivalent type normalization.

Schema Notes

• Use Schema.Struct(...).annotate({ identifier }) for named OpenAPI refs when handlers return plain objects.
• Use Schema.Class only when the handler returns real class instances or the constructor requirement is intentional.
• Keep nested anonymous shapes as Schema.Struct unless a named SDK type is useful.
• Avoid parallel hand-written Zod and Effect definitions for the same route boundary.

Phases

1. Stabilize The Bridge

Before porting more routes, cover the bridge behavior that every route depends on.

• Add tests that hit the Hono-mounted HttpApi bridge, not just HttpApiBuilder.layer directly.
• Cover auth disabled, Basic auth success, auth_token success, missing credentials, and bad credentials.
• Cover directory and x-opencode-directory instance selection.
• Verify generated SDK output remains unchanged for non-SDK work.
• Fix or remove any implemented-but-unmounted HttpApi groups.

2. Complete The Inventory

Create a route inventory from the actual Hono registrations and classify each route.

Statuses:

• bridged: served through the HttpApi bridge when the flag is on.
• implemented: HttpApi group exists but is not mounted through Hono.
• next: good JSON candidate for near-term porting.
• later: portable, but needs schema/service cleanup first.
• special: SSE, websocket, streaming, or UI bridge behavior that likely needs raw Effect HTTP rather than HttpApi.

3. Finish JSON Route Parity

Port remaining JSON routes in small batches.

Good near-term candidates:

• top-level reads: GET /path, GET /vcs, GET /vcs/diff, GET /command, GET /agent, GET /skill, GET /lsp, GET /formatter
• simple mutations: POST /instance/dispose
• experimental JSON reads: console, tool, worktree list, resource list
• deferred JSON mutations: workspace/worktree create/remove/reset, file search, MCP auth flows

Keep large or stateful groups for later:

• session
• sync
• process-level experimental routes

4. Move OpenAPI And SDK Generation

Hono routes cannot be deleted while hono-openapi is the source of SDK generation.

Status: the Effect HttpApi OpenAPI surface is implemented and opt-in (bun dev generate --httpapi, OPENCODE_SDK_OPENAPI=httpapi). Default SDK generation still uses Hono. httpapi/public.ts applies the Hono-compat normalization layer to the Effect output. Diff against the Hono-generated spec still shows real gaps that must be closed before the SDK can flip:

• Branded-type pattern constraints on ID schemas are not propagated to the Effect output (~169 missing).
• Per-property description annotations are not propagated through Schema.Struct to the Effect output (~107 missing).
• Event.* and SyncEvent.* component names use dotted form in Hono and PascalCase in Effect (~50 differences, breaks SDK type names).
• Effect's component deduper emits numbered duplicates (Session9, SyncEvent.session.updated.11) that need a name-collision fix.
• Cosmetic-only diffs (additionalProperties: false, const vs enum, MAX_SAFE_INTEGER maximum, propertyNames) can be normalized in public.ts if they would otherwise change SDK output.

Required before route deletion:

• Close the diff above so Effect-generated SDK output matches the Hono-generated SDK output for every retained path.
• Keep operation IDs, schemas, status codes, and SDK type names stable unless the change is intentional.
• Flip packages/sdk/js/script/build.ts default to httpapi and regenerate.
• Compare generated SDK output against dev for every route group deletion.
• Remove Hono OpenAPI stubs only after Effect OpenAPI is the SDK source for those paths.

V2 cleanup once SDK compatibility no longer needs the legacy Hono contract:

• Remove public.ts compatibility transforms that hide honest HttpApi metadata, including auth securitySchemes, per-route security, and generated 401 responses.
• Stop remapping built-in HttpApi error schemas back to legacy Hono BadRequestError / NotFoundError components if V2 clients can consume the actual Effect error shape.
• Prefer the direct HttpApi OpenAPI output for request/response bodies and named component schemas instead of rewriting it to match Hono generator quirks.
• Keep schema fixes that describe the actual wire format, but delete transforms that only preserve legacy SDK type names or inline-vs-ref shape.
• Re-evaluate auth_token as an OpenAPI security scheme rather than a hand-injected query parameter once clients can consume the V2 spec.

5. Make HttpApi Default For JSON Routes

After JSON parity and SDK generation are covered:

• Flip the bridge default for ported JSON routes.
• Keep a short-lived fallback flag for the old Hono implementation.
• Run the same tests against both the default and fallback path during rollout.
• Stop adding new Hono handlers for JSON routes once the default flips.

6. Delete Hono Route Implementations

Delete Hono routes group-by-group after each group meets the deletion criteria.

Deletion criteria:

• HttpApi route is mounted by default.
• Behavior is covered by bridge-level tests.
• OpenAPI/SDK generation comes from Effect for that path.
• SDK diff is zero or explicitly accepted.
• Legacy Hono route is no longer needed as a fallback.

After deleting a group:

• Remove its Hono route file or dead endpoints.
• Remove its .route(...) registration from instance/index.ts.
• Remove duplicate Zod-only route DTOs if Effect Schema now owns the type.
• Regenerate SDK and verify output.

7. Replace Special Routes

Special routes need explicit designs before Hono can disappear completely.

• event: SSE
• pty: websocket
• tui: UI/control bridge behavior
• streaming session endpoints

Use raw Effect HTTP routes where HttpApi does not fit. The goal is deleting Hono implementations, not forcing every transport shape through HttpApi.

Current Route Status

Area	Status	Notes
question	bridged	GET /question, reply, reject
permission	bridged	list and reply
provider	bridged	list, auth, OAuth authorize/callback
config	bridged	read, providers, update
project	bridged	list, current, git init, update
file	bridged partial	find text/file/symbol, list/content/status
mcp	bridged	status, add, OAuth, connect/disconnect
workspace	bridged	adapter/list/status/create/remove/session-restore
top-level instance routes	bridged	path, vcs, command, agent, skill, lsp, formatter, dispose
experimental JSON routes	bridged	console, tool, worktree list/mutations, global session list, resource list
session	bridged	read, lifecycle, prompt, message/part mutations, revert, permission reply
sync	bridged	start/replay/history
event	bridged	SSE via raw Effect HTTP
pty	special	websocket
tui	special	UI bridge

Full Route Checklist

This checklist tracks bridge parity only. Checked routes are available through the experimental HttpApi bridge; Hono deletion is tracked separately by the deletion checklist above.

Top-Level Instance Routes

• POST /instance/dispose - dispose active instance after response.
• GET /path - current directory and worktree paths.
• GET /vcs - current VCS status.
• GET /vcs/diff - VCS diff summary.
• GET /command - command catalog.
• GET /agent - agent catalog.
• GET /skill - skill catalog.
• GET /lsp - LSP status.
• GET /formatter - formatter status.

Config Routes

• GET /config - read config.
• PATCH /config - update config and dispose active instance after response.
• GET /config/providers - config provider summary.

Project Routes

• GET /project - list projects.
• GET /project/current - current project.
• POST /project/git/init - initialize git and reload active instance after response.
• PATCH /project/:projectID - update project metadata.

Provider Routes

• GET /provider - list providers.
• GET /provider/auth - list provider auth methods.
• POST /provider/:providerID/oauth/authorize - start provider OAuth.
• POST /provider/:providerID/oauth/callback - finish provider OAuth.

Question Routes

• GET /question - list questions.
• POST /question/:requestID/reply - reply to question.
• POST /question/:requestID/reject - reject question.

Permission Routes

• GET /permission - list permission requests.
• POST /permission/:requestID/reply - reply to permission request.

File Routes

• GET /find - text search.
• GET /find/file - file search.
• GET /find/symbol - symbol search.
• GET /file - list directory entries.
• GET /file/content - read file content.
• GET /file/status - file status.

MCP Routes

• GET /mcp - MCP status.
• POST /mcp - add MCP server at runtime.
• POST /mcp/:name/auth - start MCP OAuth.
• POST /mcp/:name/auth/callback - finish MCP OAuth callback.
• POST /mcp/:name/auth/authenticate - run MCP OAuth authenticate flow.
• DELETE /mcp/:name/auth - remove MCP OAuth credentials.
• POST /mcp/:name/connect - connect MCP server.
• POST /mcp/:name/disconnect - disconnect MCP server.

Experimental Routes

• GET /experimental/console - active Console provider metadata.
• GET /experimental/console/orgs - switchable Console orgs.
• POST /experimental/console/switch - switch active Console org.
• GET /experimental/tool/ids - tool IDs.
• GET /experimental/tool - tools for provider/model.
• GET /experimental/worktree - list worktrees.
• POST /experimental/worktree - create worktree.
• DELETE /experimental/worktree - remove worktree.
• POST /experimental/worktree/reset - reset worktree.
• GET /experimental/session - global session list.
• GET /experimental/resource - MCP resources.

Workspace Routes

• GET /experimental/workspace/adapter - list workspace adapters.
• POST /experimental/workspace - create workspace.
• GET /experimental/workspace - list workspaces.
• GET /experimental/workspace/status - workspace status.
• DELETE /experimental/workspace/:id - remove workspace.
• POST /experimental/workspace/:id/session-restore - restore session into workspace.

Sync Routes

• POST /sync/start - start workspace sync.
• POST /sync/replay - replay sync events.
• POST /sync/history - list sync event history.

Session Routes

• GET /session - list sessions.
• GET /session/status - session status map.
• GET /session/:sessionID - get session.
• GET /session/:sessionID/children - get child sessions.
• GET /session/:sessionID/todo - get session todos.
• POST /session - create session.
• DELETE /session/:sessionID - delete session.
• PATCH /session/:sessionID - update session metadata.
• POST /session/:sessionID/init - run project init command.
• POST /session/:sessionID/fork - fork session.
• POST /session/:sessionID/abort - abort session.
• POST /session/:sessionID/share - share session.
• GET /session/:sessionID/diff - session diff.
• DELETE /session/:sessionID/share - unshare session.
• POST /session/:sessionID/summarize - summarize session.
• GET /session/:sessionID/message - list session messages.
• GET /session/:sessionID/message/:messageID - get message.
• DELETE /session/:sessionID/message/:messageID - delete message.
• DELETE /session/:sessionID/message/:messageID/part/:partID - delete part.
• PATCH /session/:sessionID/message/:messageID/part/:partID - update part.
• POST /session/:sessionID/message - prompt with streaming response.
• POST /session/:sessionID/prompt_async - async prompt.
• POST /session/:sessionID/command - run command.
• POST /session/:sessionID/shell - run shell command.
• POST /session/:sessionID/revert - revert message.
• POST /session/:sessionID/unrevert - restore reverted messages.
• POST /session/:sessionID/permissions/:permissionID - deprecated permission response route.

Event Routes

• GET /event - SSE event stream via raw Effect HTTP.

PTY Routes

• GET /pty - list PTY sessions.
• POST /pty - create PTY session.
• GET /pty/:ptyID - get PTY session.
• PUT /pty/:ptyID - update PTY session.
• DELETE /pty/:ptyID - remove PTY session.
• GET /pty/:ptyID/connect - PTY websocket; replace with raw Effect HTTP/websocket support.

TUI Routes

• POST /tui/append-prompt - append prompt.
• POST /tui/open-help - open help.
• POST /tui/open-sessions - open sessions.
• POST /tui/open-themes - open themes.
• POST /tui/open-models - open models.
• POST /tui/submit-prompt - submit prompt.
• POST /tui/clear-prompt - clear prompt.
• POST /tui/execute-command - execute command.
• POST /tui/show-toast - show toast.
• POST /tui/publish - publish TUI event.
• POST /tui/select-session - select session.
• GET /tui/control/next - get next TUI request.
• POST /tui/control/response - submit TUI control response.

Remaining PR Plan

Prefer smaller PRs from here so route behavior and SDK/OpenAPI fallout stays reviewable.

1. Bridge PATCH /project/:projectID.
2. Bridge MCP add/connect/disconnect routes.
3. Bridge MCP OAuth routes: start, callback, authenticate, remove.
4. Bridge experimental console switch and tool list routes.
5. Bridge experimental global session list.
6. Bridge workspace create/remove/session-restore routes.
7. Bridge sync start/replay/history routes.
8. Bridge session read routes: list, status, get, children, todo, diff, messages.
9. Bridge session lifecycle mutation routes: create, delete, update, fork, abort.
10. Bridge remaining session mutation and prompt routes.
11. Replace event SSE with non-Hono Effect HTTP. The Effect backend has a raw Effect HTTP httpapi/event.ts; the Hono backend still uses hono/streaming streamSSE. Either port Hono /event to raw Effect HTTP for the fallback window, or skip and delete it together with Hono in step 15.
12. Replace pty websocket/control routes with non-Hono Effect HTTP for the Effect backend. Hono pty.ts remains in the Hono backend.
13. Replace tui bridge routes or explicitly isolate them behind a non-Hono compatibility layer for the Effect backend. Hono tui.ts remains in the Hono backend.
14. Switch OpenAPI/SDK generation to Effect routes and compare SDK output. Effect path is implemented and opt-in via --httpapi / OPENCODE_SDK_OPENAPI=httpapi. Close the schema-shape gaps in public.ts (branded pattern, per-property description, Event.* / SyncEvent.* naming, dedup collisions), then flip packages/sdk/js/script/build.ts default.
15. Flip backend.ts default from hono to effect-httpapi, keep OPENCODE_EXPERIMENTAL_HTTPAPI (or its inverse) as a short fallback flag, then delete replaced Hono route files.

Checklist

• Add first HttpApi JSON route slices.
• Bridge selected HttpApi routes behind OPENCODE_EXPERIMENTAL_HTTPAPI. (Now backend-fork-at-startup rather than in-Hono path mounting.)
• Reuse existing Effect services in handlers.
• Provide auth, instance lookup, and observability in the Effect route layer.
• Centralize auth via Effect Config for the Effect backend.
• Support auth_token as a query security scheme.
• Add bridge-level auth and instance tests.
• Complete exact Hono route inventory.
• Resolve implemented-but-unmounted route groups.
• Port remaining top-level JSON reads.
• Implement Effect HttpApi OpenAPI generation behind --httpapi / OPENCODE_SDK_OPENAPI=httpapi.
• Close Effect-vs-Hono OpenAPI schema-shape gaps and flip the SDK generator default.
• Flip the runtime backend default from hono to effect-httpapi, with a short fallback flag.
• Delete replaced Hono route implementations.
• Replace SSE/websocket/streaming Hono routes with non-Hono implementations (or remove with the rest of Hono).