feat: register isphere receive messages tool

docs/superpowers/plans/2026-07-09-stage-c-log-backed-receive-messages-loop.md

@@ -655,7 +655,7 @@ Implemented and verified in this loop:
 - Tool source: `isphere.EncryptedPacketLogSource.ReceiveMessages(ctx, isphere.ReceiveMessagesQuery{Limit: input.Limit})`.
 - Tool output shape: a map/object with `messages`, where each message carries `id`, `conversation_id`, `conversation_type`, `sender_id`, `receiver_id`, `text`, `timestamp`, `subject`, `receipt_id`, and `read`.
 
-- [ ] **Step 1: Write failing tool registration tests**
+- [x] **Step 1: Write failing tool registration tests**
 
 Add or update tests so they fail before implementation:
 
@@ -666,19 +666,19 @@ go test ./internal/mcpserver -run TestNewServerRegistersN8WinHelperToolsWithoutC
 
 Expected initial failures: `isphere_receive_messages` is not registered and the server/tool lists still expose only the four helper tools.
 
-- [ ] **Step 2: Implement `internal/tools/isphere_read.go`**
+- [x] **Step 2: Implement `internal/tools/isphere_read.go`**
 
 Register `isphere_receive_messages` with `mcp.AddTool`, convert the C2 `isphere.Message` slice into the explicit JSON/map output shape, and keep the only public input parameter as `limit`. Use a source interface so tests can inject a synthetic C2 source without raw evidence files.
 
-- [ ] **Step 3: Register business read tool in `mcpserver.NewServer`**
+- [x] **Step 3: Register business read tool in `mcpserver.NewServer`**
 
 Register the helper tools plus `isphere_receive_messages`. If no live log-line loader exists yet, wire an empty `isphere.EncryptedPacketLogSource{}` as the default so registration is testable without committing raw logs.
 
-- [ ] **Step 4: Update existing helper-tool guard tests**
+- [x] **Step 4: Update existing helper-tool guard tests**
 
 Rename or adjust the old “exactly four” helper test so it still blocks forbidden write/sending tool names but explicitly allows `isphere_receive_messages`. Update `internal/mcpserver/server_test.go` to expect five tools: four helper tools plus `isphere_receive_messages`.
 
-- [ ] **Step 5: Run full verification**
+- [x] **Step 5: Run full verification**
 
 Run:
 
@@ -690,22 +690,75 @@ go build ./cmd/isphere-mcp
 
 Expected: all exit 0.
 
-- [ ] **Step 6: Commit Loop C3 and rewrite Loop C4**
+- [x] **Step 6: Commit Loop C3 and rewrite Loop C4**
 
 Commit exact C3 paths only. Rewrite Loop C4 around the actual MCP tool output shape and the fact that default server wiring has no raw evidence loader yet.
 
 ---
 
+## Loop C3 Result
+
+Implemented and verified in this loop:
+
+- `internal/tools.RegisterISphereReadTools(server, source)` registers `isphere_receive_messages` with a single public input parameter: `limit`.
+- `internal/tools.ToolNameReceiveMessages` is `isphere_receive_messages`.
+- The tool calls the C2 source interface with `isphere.ReceiveMessagesQuery{Limit: input.Limit}` and returns structured content shaped as `messages: [{ id, conversation_id, conversation_type, sender_id, receiver_id, text, timestamp, subject, receipt_id, read }]`.
+- `internal/mcpserver.NewServer()` now registers four WinHelper observation tools plus `isphere_receive_messages`; default source wiring uses an empty `isphere.EncryptedPacketLogSource{}` so no raw evidence is committed or loaded by default.
+- Guard tests still keep helper tools scoped to helper observation operations while allowing `receive` as a legitimate read capability name for the new business tool.
+- Verification completed for C3 with `git diff --check`, `go test ./...`, and `go build ./cmd/isphere-mcp`; the generated root `isphere-mcp.exe` build artifact was removed.
+- Loop C4 was rewritten around the actual five-tool surface and empty default source behavior.
+
+---
+
 ## Loop C4: Operator verification and docs
 
-**Current draft goal:** Add a verification command or fixture-backed smoke test for `isphere_receive_messages` and update user-facing docs.
+**Goal:** Update the repeatable operator verification and user-facing docs for the five-tool surface after C3 registers `isphere_receive_messages`.
 
 **Planned files:**
 - Modify: `scripts/verify-go-mcp.ps1`
 - Modify: `docs/go-mcp-runbook.md`
 - Modify: `docs/current-status-card.md`
+- Modify: `docs/superpowers/plans/2026-07-09-stage-c-log-backed-receive-messages-loop.md`
 
-**Rewrite rule before implementation:** Only write this loop after C3 confirms the actual MCP response shape.
+**Interfaces from Loop C3:**
+- Server tool list: four WinHelper observation tools plus `isphere_receive_messages`.
+- Default `isphere_receive_messages` source: `isphere.EncryptedPacketLogSource{}` with no configured lines, so the operator smoke call should return `messages: []` until a real evidence loader is wired.
+- Verification script should still call `win_helper_version`, and should additionally call `isphere_receive_messages` with a small `limit` and assert the returned `messages` field is an array.
+
+- [ ] **Step 1: Capture current verification red state**
+
+Run before editing the script:
+
+```powershell
+powershell -NoProfile -ExecutionPolicy Bypass -File scripts/verify-go-mcp.ps1
+```
+
+Expected: FAIL because the existing harness still expects exactly four tools and treats `receive` as a forbidden term.
+
+- [ ] **Step 2: Update `scripts/verify-go-mcp.ps1`**
+
+Change expected tools to five, remove `receive` from the forbidden write/scope terms, and add an SDK call to `isphere_receive_messages` with `{ "limit": 5 }`. Assert `messages` exists and is an array; for the default empty source, assert the smoke result has zero messages.
+
+- [ ] **Step 3: Update operator docs**
+
+Update `docs/go-mcp-runbook.md` and `docs/current-status-card.md` so they describe the current five-tool surface, the empty default read source, and the fact that raw N12-pre evidence still stays under ignored `runs/` paths.
+
+- [ ] **Step 4: Run full verification**
+
+Run:
+
+```powershell
+git diff --check
+go test ./...
+go build ./cmd/isphere-mcp
+powershell -NoProfile -ExecutionPolicy Bypass -File scripts/verify-go-mcp.ps1
+```
+
+Expected: all exit 0. Remove any generated root `isphere-mcp.exe` after build.
+
+- [ ] **Step 5: Commit Loop C4 and rewrite next loop**
+
+Commit exact C4 paths only. Rewrite the next loop around the remaining gap: a safe configurable source loader or fixture path for `isphere_receive_messages`, without committing raw evidence.
 
 ---