# TP-033-streamable-http-transport: TP-033-streamable-http-transport — Status

**Current Step:** Complete
**Status:** ✅ Complete
**Last Updated:** 2026-05-14
**Review Level:** 2
**Review Counter:** 13
**Iteration:** 1
**Size:** M

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### Step 1: Transport selection plumbing

**Status:** ✅ Complete

- [x] Config/flag selects `stdio` (default) or `http`; HTTP bind defaults to `127.0.0.1:<port>`.
- [x] Non-loopback bind requires an explicit config value and logs a clear WARNING when active.
- [x] Invalid transport and bind values fail loudly at startup.

### Step 2: Streamable HTTP transport

**Status:** ✅ Complete

- [x] Wire the Go SDK Streamable HTTP transport onto the shared server core; the tool/resource/prompt registry is identical across transports.
- [x] Single shared server lifecycle (startup/shutdown, context cancellation honored).
- [x] Graceful shutdown closes the listener and in-flight requests cleanly.

### Step 3: Security posture

**Status:** ✅ Complete

- [x] Default bind is loopback only; confirm with a test that the default config never produces a non-loopback listener.
- [x] No API keys or athlete IDs in HTTP logs; reuse the existing redaction conventions.
- [x] Document the LAN-bind threat model briefly in README (anyone on the LAN can reach the server with no auth — opt in deliberately).

### Step 4: Parity tests

**Status:** ✅ Complete

- [x] The same protocol tests that cover stdio (initialize, tools/list, tool calls, resources, prompts, malformed requests, sanitized errors) run against the HTTP transport.
- [x] Handler behaviour is byte-identical across transports — assert this where practical.

### Step 5: Docs

**Status:** ✅ Complete

- [x] README: transport selection, default loopback bind, opt-in LAN bind + security note.
- [x] CHANGELOG `[Unreleased]` entry.

### Step 6: Verify

**Status:** ✅ Complete

- [x] `make test`
- [x] `make build`
- [x] `make lint`
- [x] `go test -race ./...`
- [x] Manual: start in `http` mode; confirm it binds `127.0.0.1` only by default; drive a tool call over HTTP from one MCP client.

---

## Reviews

| #    | Type | Step | Verdict | File                          |
| ---- | ---- | ---- | ------- | ----------------------------- |
| R001 | plan | 1    | REVISE  | `.reviews/R001-plan-step1.md` |
| R002 | plan | 1    | APPROVE | `.reviews/R002-plan-step1.md` |
| R003 | code | 1    | APPROVE | `.reviews/R003-code-step1.md` |
| R004 | plan | 2    | APPROVE | `.reviews/R004-plan-step2.md` |
| R005 | code | 2    | APPROVE | `.reviews/R005-code-step2.md` |
| R006 | plan | 3    | APPROVE | `.reviews/R006-plan-step3.md` |
| R007 | code | 3    | APPROVE | `.reviews/R007-code-step3.md` |
| R008 | plan | 4    | APPROVE | `.reviews/R008-plan-step4.md` |
| R009 | code | 4    | APPROVE | `.reviews/R009-code-step4.md` |
| R010 | plan | 5    | APPROVE | `.reviews/R010-plan-step5.md` |
| R011 | code | 5    | APPROVE | `.reviews/R011-code-step5.md` |
| R012 | plan | 6    | APPROVE | `.reviews/R012-plan-step6.md` |
| R013 | code | 6    | APPROVE | `.reviews/R013-code-step6.md` |

---

## Discoveries

| Discovery                                                                                                                                                                                     | Disposition                                                                                                                                     | Location                                          |
| --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------- |
| Current worktree already contains the Streamable HTTP implementation from the previous merged TP-033 history; this iteration is auditing, re-verifying, and restoring current task artifacts. | Use existing implementation where it satisfies the prompt; do not duplicate handler logic.                                                      | `internal/config`, `internal/app`, `internal/mcp` |
| Initial `make test` exposed stale prompt golden fixtures unrelated to HTTP transport; rendered prompt output is current and fixtures had extra blank/indented lines.                          | Updated `internal/prompts/testdata/*.md` to match the renderer and confirmed `go test ./internal/prompts` passes before retrying the full gate. | `internal/prompts/testdata`                       |

---

## Execution Log

| Timestamp        | Action            | Outcome                                                                                                                                                                                                                                                |
| ---------------- | ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------------- | -------------------------------------- |
| 2026-05-14       | Task staged       | Scaffolded from ROADMAP.md v0.4                                                                                                                                                                                                                        |
| 2026-05-14 19:48 | Task started      | Runtime V2 lane-runner execution                                                                                                                                                                                                                       |
| 2026-05-14 19:48 | Step 1 started    | Transport selection plumbing                                                                                                                                                                                                                           |
| 2026-05-14 19:50 | Review R001       | plan Step 1: REVISE; added concrete plan details below before marking work complete                                                                                                                                                                    |
| 2026-05-14 19:54 | Review R002       | plan Step 1: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 19:55 | Step 1 checkpoint | Config and CLI transport selection audited in `internal/config` and `internal/app`; `go test ./internal/config ./internal/app` passed.                                                                                                                 |
| 2026-05-14 19:56 | Step 1 checkpoint | Non-loopback explicit bind and WARN path audited in `internal/config`/`internal/app`; logs avoid API keys and athlete IDs.                                                                                                                             |
| 2026-05-14 19:57 | Step 1 checkpoint | Invalid transport and bind values fail in config validation.                                                                                                                                                                                           |
| 2026-05-14 19:58 | Recovery          | Reverted premature Step 1 completion before required code review.                                                                                                                                                                                      |
| 2026-05-14 19:57 | Review R003       | code Step 1: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 19:59 | Step 1 complete   | Transport selection plumbing audited and approved; Step 2 started.                                                                                                                                                                                     |
| 2026-05-14 19:59 | Review R004       | plan Step 2: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:00 | Step 2 checkpoint | Shared SDK server and `NewStreamableHTTPHandler` wiring audited in `internal/mcp`; `go test ./internal/mcp ./internal/app` passed.                                                                                                                     |
| 2026-05-14 20:01 | Step 2 checkpoint | Startup/shutdown paths use one `Server` wrapper for stdio and HTTP with context cancellation honored.                                                                                                                                                  |
| 2026-05-14 20:02 | Step 2 checkpoint | Graceful shutdown and listener-close tests audited in `TestServeStreamableHTTPCancelClosesListener`.                                                                                                                                                   |
| 2026-05-14 20:01 | Review R005       | code Step 2: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:03 | Step 2 complete   | Streamable HTTP transport wiring and lifecycle audited and approved; Step 3 started.                                                                                                                                                                   |
| 2026-05-14 20:03 | Review R006       | plan Step 3: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:04 | Step 3 checkpoint | Default loopback bind audited in config tests; `go test ./internal/config ./internal/mcp ./internal/app` passed.                                                                                                                                       |
| 2026-05-14 20:05 | Step 3 checkpoint | HTTP log redaction tests audited for malformed requests, startup/listen/shutdown, API keys, and athlete IDs.                                                                                                                                           |
| 2026-05-14 20:06 | Step 3 checkpoint | README LAN-bind threat model audited.                                                                                                                                                                                                                  |
| 2026-05-14 20:06 | Review R007       | code Step 3: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:07 | Step 3 complete   | Security posture audited and approved; Step 4 started.                                                                                                                                                                                                 |
| 2026-05-14 20:08 | Review R008       | plan Step 4: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:09 | Step 4 checkpoint | Shared protocol suite audited across in-memory and Streamable HTTP; `go test ./internal/mcp` passed.                                                                                                                                                   |
| 2026-05-14 20:10 | Step 4 checkpoint | `TestProtocolTransportParity` byte-comparison audited for stable handler responses across transports.                                                                                                                                                  |
| 2026-05-14 20:11 | Review R009       | code Step 4: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:12 | Step 4 verify     | `go test ./internal/mcp -run 'TestProtocol(SharedTransportSuite                                                                                                                                                                                        | TransportParity | MalformedHTTPPost)$' -count=1` passed. |
| 2026-05-14 20:12 | Step 4 complete   | Parity tests audited and approved; Step 5 started.                                                                                                                                                                                                     |
| 2026-05-14 20:12 | Review R010       | plan Step 5: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:13 | Step 5 checkpoint | README transport docs audited for selection, loopback default, config fields, invalid startup failure, and LAN warning.                                                                                                                                |
| 2026-05-14 20:14 | Step 5 checkpoint | CHANGELOG `[Unreleased]` Streamable HTTP entry audited.                                                                                                                                                                                                |
| 2026-05-14 20:16 | Review R011       | code Step 5: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:17 | Step 5 complete   | Docs audited and approved; Step 6 started.                                                                                                                                                                                                             |
| 2026-05-14 20:18 | Review R012       | plan Step 6: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:20 | Verify            | Initial `make test` failed in `internal/prompts` due stale golden fixtures; updated fixtures and `go test ./internal/prompts` passed.                                                                                                                  |
| 2026-05-14 20:22 | Verify            | `make test` passed after refreshing prompt golden fixtures.                                                                                                                                                                                            |
| 2026-05-14 20:23 | Verify            | `make build` passed.                                                                                                                                                                                                                                   |
| 2026-05-14 20:24 | Verify            | `make lint` passed.                                                                                                                                                                                                                                    |
| 2026-05-14 20:25 | Verify            | `go test -race ./...` passed.                                                                                                                                                                                                                          |
| 2026-05-14 20:26 | Verify            | Manual HTTP smoke passed: started `./bin/icuvisor` with `ICUVISOR_TRANSPORT=http`, confirmed log and `lsof` listener were `127.0.0.1:8765` only, then used a Go SDK Streamable HTTP client for `tools/list` and `icuvisor_list_advanced_capabilities`. |
| 2026-05-14 20:26 | Review R013       | code Step 6: APPROVE                                                                                                                                                                                                                                   |
| 2026-05-14 20:27 | Step 6 complete   | Verification passed and code review approved.                                                                                                                                                                                                          |
| 2026-05-14 20:27 | Task complete     | .DONE created.                                                                                                                                                                                                                                         |
| 2026-05-14 20:27 | Worker iter 1 | done in 2355s, tools: 145 |
| 2026-05-14 20:27 | Task complete | .DONE created |

---

## Blockers

_None_

---

## Notes

- Go SDK Streamable HTTP docs: MCP Go SDK Streamable HTTP handler docs and MCP Go SDK Streamable HTTP client transport docs
- Step 1 plan: expose config JSON fields `transport` and `http_bind`, `.env`/process env keys `ICUVISOR_TRANSPORT` and `ICUVISOR_HTTP_BIND`, and CLI overrides `--transport`/`--http-bind`; precedence is JSON < `.env` for absent values < process env < CLI options. `cmd/icuvisor/main.go` stays thin and delegates to `internal/app`, which owns flag parsing.
- Step 1 validation plan: default transport is `stdio`; HTTP mode is selected only by explicit `http`; default HTTP bind is `127.0.0.1:8765`. Accepted transports are exactly `stdio` and `http`. Bind parsing requires explicit IP host plus numeric port 1-65535 (IPv4 and bracketed IPv6 accepted), rejects wildcard-by-omission such as `:8765`, URL strings, missing port, non-numeric port, and out-of-range port. Non-loopback addresses are accepted only when explicitly configured because the default is loopback.
- Step 1 warning/test plan: log a structured WARN only when `transport=http` and the active bind is non-loopback; include transport and bind address only, never API keys or raw athlete IDs. Cover defaults, JSON/env/CLI selection, invalid transport/bind errors, non-loopback detection, and backward-compatible `version`, `--config path`, and `--config=path` CLI parsing.
- Step 2 plan: keep `internal/mcp.NewServer` as the single shared SDK server/registry constructor. For stdio, keep `Server.Run(ctx)` over `sdkmcp.StdioTransport`. For HTTP, serve the same SDK server through `sdkmcp.NewStreamableHTTPHandler(func(*http.Request) *sdkmcp.Server { return sharedSDKServer }, options)` mounted at `/mcp`; do not duplicate tool/resource/prompt registration or handler logic.
- Step 2 lifecycle plan: `RunStreamableHTTP` owns `net.Listen`, `ServeStreamableHTTP` accepts an injected listener for tests, uses `http.Server` with request contexts rooted in the worker context, treats `http.ErrServerClosed` as expected, and on cancellation calls bounded `Shutdown` followed by `Close` if needed. Tests cover app transport dispatch, HTTP initialize smoke, and cancellation closing the listener.
- Step 3 plan: verify the default HTTP bind remains `127.0.0.1:8765` and is loopback via `internal/config` tests; keep non-loopback binds explicit and WARN-only. Audit HTTP logs for startup/listen/shutdown/malformed request paths to ensure no API keys, tokens, raw athlete IDs, or request payloads are logged.
- Step 3 docs plan: README must state the LAN-bind threat model clearly: Streamable HTTP has no auth in this task, so anyone on the LAN who can reach the bind address can invoke registered tools with the configured intervals.icu credentials.
- Step 4 plan: audit the shared protocol suite in `internal/mcp/protocol_test.go`, where `connectProtocolClient` runs scenarios against in-memory/stdio-equivalent SDK transport and Streamable HTTP. Coverage must include initialize, tools/list, successful tool call, missing tool, sanitized tool errors, resources list/read/not-found/sanitized errors, prompts list/get, and malformed HTTP requests.
- Step 4 parity plan: confirm `TestProtocolTransportParity` serializes stable SDK results to canonical JSON and byte-compares handler outputs across in-memory and Streamable HTTP transports where practical.
- Step 5 plan: audit README for transport selection via `ICUVISOR_TRANSPORT=http`/`--transport http`, the default endpoint `http://127.0.0.1:8765/mcp`, config fields `transport`/`http_bind`, invalid config startup failure, and LAN-bind security warning. Audit CHANGELOG `[Unreleased]` for a concise Streamable HTTP entry.
- Step 6 plan: run required gates in order: `make test`, `make build`, `make lint`, and `go test -race ./...`. For manual smoke, start `./bin/icuvisor` with `ICUVISOR_TRANSPORT=http` and sentinel env config without `--http-bind`, confirm logs/listener show `127.0.0.1:8765` only, then use a tiny Go SDK Streamable HTTP client against `http://127.0.0.1:8765/mcp` to run `tools/list` and a no-network `icuvisor_list_advanced_capabilities` tool call.
