---
phase: 01-foundation-types-and-store-contract
verified: 2026-02-21T23:45:00Z
status: passed
score: 13/13 must-haves verified
gaps: []
human_verification: []
---

# Phase 1: Foundation Types and Store Contract — Verification Report

**Phase Goal:** Developers can depend on `pmcp-tasks` and use correct, spec-compliant types that serialize to match the MCP 2025-11-25 schema exactly

**Verified:** 2026-02-21T23:45:00Z
**Status:** PASSED
**Re-verification:** No — initial verification

---

## Goal Achievement

### Observable Truths

| #  | Truth | Status | Evidence |
|----|-------|--------|----------|
| 1  | `pmcp-tasks` crate compiles as a workspace member with `cargo check --package pmcp-tasks` | VERIFIED | `cargo check` exits 0; `crates/pmcp-tasks` in workspace members at `Cargo.toml:405` |
| 2  | `TaskStatus` enum serializes to snake_case matching spec (working, input_required, completed, failed, cancelled) | VERIFIED | `#[serde(rename_all = "snake_case")]` on enum; 36 protocol tests pass including `test_task_status_serializes_snake_case` |
| 3  | `Task` wire type serializes `ttl` as null (not omitted) when None, and omits `pollInterval` when None | VERIFIED | No `skip_serializing_if` on `ttl` field; `#[serde(skip_serializing_if = "Option::is_none")]` on `poll_interval`; `test_task_ttl_null_serialization` passes |
| 4  | `CreateTaskResult` wraps `Task` in a `task` field; `GetTaskResult` and `CancelTaskResult` are flat `Task` aliases | VERIFIED | `CreateTaskResult { task: Task, _meta: ... }`; `pub type GetTaskResult = Task`; `pub type CancelTaskResult = Task`; confirmed by `test_create_task_result_wraps_task` and `test_get_task_result_is_flat` |
| 5  | State machine rejects invalid transitions (terminal states reject all, self-transitions rejected) | VERIFIED | `can_transition_to` returns false for self and for all targets from terminal states; 46 state machine tests pass covering full 5x5 matrix |
| 6  | All request param types, capability types, notification type, and execution types serialize to match spec schema | VERIFIED | All types have `#[serde(rename_all = "camelCase")]`; 36 protocol_types tests verify round-trips for `TaskParams`, `TaskGetParams`, `TaskResultParams`, `TaskListParams`, `TaskCancelParams`, `ServerTaskCapabilities`, `ClientTaskCapabilities`, `TaskStatusNotification`, `TaskSupport`, `ToolExecution` |
| 7  | `TaskError` enum has rich context variants with JSON-RPC error code mapping | VERIFIED | 8 variants with context fields; `error_code()` maps to -32602 (InvalidParams) or -32603 (InternalError); manual Display impl includes task_id, status, etc. |
| 8  | `TaskRecord` struct holds protocol Task fields plus owner_id, variables, result, and request_method | VERIFIED | `pub struct TaskRecord` has all 6 fields; `TaskRecord::new()` generates UUIDv4 task_id and computes expires_at |
| 9  | `TaskWithVariables` wraps a Task and a HashMap of variables, injecting variables into `_meta` at serialization boundary | VERIFIED | `TaskWithVariables::to_wire_task()` injects variables at top level of `_meta`; `from_record()` constructor; 5 unit tests pass |
| 10 | `TaskStore` async trait defines all 10 methods including atomic `complete_with_result` | VERIFIED | Trait has 11 methods (create, get, update_status, set_variables, set_result, get_result, complete_with_result, list, cancel, cleanup_expired, config); all with doc comments and error documentation |
| 11 | `TaskStore` trait enforces configurable variable size limits in trait contract | VERIFIED | `StoreConfig` with `max_variable_size_bytes`, `default_ttl_ms`, `max_ttl_ms`; `config() -> &StoreConfig` on trait |
| 12 | All wire types round-trip through serde_json and produce JSON matching the MCP 2025-11-25 spec exactly | VERIFIED | 36 protocol_types integration tests pass; 9 proptest property tests cover arbitrary round-trips |
| 13 | Property tests verify state machine invariants, serde round-trip stability, and TTL correctness under arbitrary inputs; fuzz-style deserialization tests verify Task and TaskStatus handle arbitrary JSON without panicking | VERIFIED | 9 proptest tests: terminal state invariant, self-transition invariant, is_terminal consistency, serde round-trips for TaskStatus and Task, fresh TaskRecord never expired, fuzz deserialization from bytes/strings/arbitrary JSON |

**Score:** 13/13 truths verified

---

### Required Artifacts

| Artifact | Expected | Status | Details |
|----------|----------|--------|---------|
| `crates/pmcp-tasks/Cargo.toml` | Crate manifest with all dependencies | VERIFIED | All required deps present: serde, serde_json, async-trait, thiserror, uuid, chrono, tokio, tracing, parking_lot, pmcp |
| `crates/pmcp-tasks/src/lib.rs` | Crate root with module declarations and re-exports | VERIFIED | `pub mod types`, `pub mod domain`, `pub mod store`, `pub mod error`, `pub mod constants`; all re-exported |
| `crates/pmcp-tasks/src/types/task.rs` | Task, TaskStatus, CreateTaskResult, GetTaskResult, CancelTaskResult wire types | VERIFIED | All types present and substantive with state machine methods |
| `crates/pmcp-tasks/src/types/params.rs` | TaskGetParams, TaskResultParams, TaskListParams, TaskCancelParams, TaskParams | VERIFIED | All 5 param types with correct serde attributes |
| `crates/pmcp-tasks/src/types/capabilities.rs` | ServerTaskCapabilities, ClientTaskCapabilities with full() and tools_only() constructors | VERIFIED | `full()` enables list+cancel+tools.call; `tools_only()` enables only tools.call |
| `crates/pmcp-tasks/src/types/notification.rs` | TaskStatusNotification type | VERIFIED | Struct with all fields matching Task wire structure; ttl as required-nullable |
| `crates/pmcp-tasks/src/types/execution.rs` | TaskSupport enum, ToolExecution metadata | VERIFIED | `TaskSupport` with Forbidden/Optional/Required; `#[default]` on Forbidden; `ToolExecution.task_support` |
| `crates/pmcp-tasks/src/error.rs` | TaskError enum with rich context and error_code() method | VERIFIED | 8 variants, manual Display/Error impls, `error_code()` mapping to JSON-RPC codes |
| `crates/pmcp-tasks/src/constants.rs` | Meta key constants and method name constants | VERIFIED | `RELATED_TASK_META_KEY`, `MODEL_IMMEDIATE_RESPONSE_META_KEY`, 5 method name constants |
| `crates/pmcp-tasks/src/domain/record.rs` | TaskRecord struct with all fields | VERIFIED | All 6 fields public; `new()`, `is_expired()`, `to_wire_task()`, `to_wire_task_with_variables()` |
| `crates/pmcp-tasks/src/domain/variables.rs` | TaskWithVariables domain type with _meta injection | VERIFIED | `from_record()`, `to_wire_task()` with top-level variable injection |
| `crates/pmcp-tasks/src/store.rs` | TaskStore async trait with all methods, ListTasksOptions, TaskPage, StoreConfig | VERIFIED | All 11 trait methods; supporting types with Debug+Clone; StoreConfig with Default impl |
| `crates/pmcp-tasks/tests/protocol_types.rs` | Serialization round-trip tests for all wire types | VERIFIED | 36 test functions; contains `test_task_serialization` pattern; imports `use pmcp_tasks::` |
| `crates/pmcp-tasks/tests/state_machine.rs` | State machine transition tests (valid and invalid) | VERIFIED | 46 test functions; contains `TaskStatus::.*can_transition_to`; organized in `mod` blocks |
| `crates/pmcp-tasks/tests/property_tests.rs` | Property-based tests using proptest | VERIFIED | 9 `proptest!` blocks; uses `arb_task_status()` and `arb_task()` strategies |

---

### Key Link Verification

| From | To | Via | Status | Details |
|------|----|-----|--------|---------|
| `src/lib.rs` | `src/types/mod.rs` | `pub mod types` | WIRED | Line 26: `pub mod types;` present and re-exported via `pub use types::*` |
| `src/types/task.rs` | `src/error.rs` | `TaskStatus` used in `TaskError::InvalidTransition` | WIRED | Line 8: `use crate::types::task::TaskStatus;` in error.rs; `from: TaskStatus` in `InvalidTransition` variant |
| `Cargo.toml` | `crates/pmcp-tasks/Cargo.toml` | workspace members list | WIRED | Line 405: `"crates/pmcp-tasks"` in workspace members |
| `src/domain/record.rs` | `src/types/task.rs` | Uses Task and TaskStatus from wire types | WIRED | Line 12: `use crate::types::task::{Task, TaskStatus};` |
| `src/domain/variables.rs` | `src/types/task.rs` | Uses Task wire type for to_wire_task conversion | WIRED | Line 16: `use crate::types::task::Task;` |
| `src/store.rs` | `src/domain/record.rs` | TaskStore methods return TaskRecord | WIRED | Line 26: `use crate::domain::TaskRecord;`; all create/get/update methods return `Result<TaskRecord, TaskError>` |
| `src/store.rs` | `src/error.rs` | TaskStore methods return Result<_, TaskError> | WIRED | Line 27: `use crate::error::TaskError;`; all trait methods return `Result<_, TaskError>` |
| `tests/protocol_types.rs` | `src/types/task.rs` | Tests Task, CreateTaskResult serialization | WIRED | Lines 9-20: `use pmcp_tasks::{..., Task, TaskStatus, ...}` |
| `tests/state_machine.rs` | `src/types/task.rs` | Tests TaskStatus::can_transition_to and validate_transition | WIRED | `use pmcp_tasks::TaskStatus` in each mod block; calls `.can_transition_to()` and `.validate_transition()` |
| `tests/property_tests.rs` | `src/types/task.rs` | Property tests over arbitrary TaskStatus and Task instances | WIRED | Line 16: `use pmcp_tasks::{Task, TaskStatus};`; uses `proptest!` macro |

---

### Requirements Coverage

| Requirement | Source Plan | Description | Status | Evidence |
|-------------|-------------|-------------|--------|----------|
| TYPE-01 | 01-01 | Protocol types (Task, TaskStatus, CreateTaskResult, TaskParams) serialize to match MCP 2025-11-25 schema exactly | SATISFIED | `Task`, `CreateTaskResult`, `GetTaskResult`, `CancelTaskResult` in `task.rs`; all serde attributes correct; 36 round-trip tests pass |
| TYPE-02 | 01-01 | TaskStatus enum supports all 5 states with serde snake_case serialization | SATISFIED | `#[serde(rename_all = "snake_case")]`; all 5 variants; `test_task_status_serializes_snake_case` passes |
| TYPE-03 | 01-01 | Task status state machine validates transitions: valid pairs enumerated, terminal states reject all | SATISFIED | `can_transition_to()` and `validate_transition()` on `TaskStatus`; 46 state machine tests cover full 5x5 matrix |
| TYPE-04 | 01-01 | Related-task metadata helper produces correct `io.modelcontextprotocol/related-task` JSON | SATISFIED | `related_task_meta()` function in task.rs; `RELATED_TASK_META_KEY` constant; doctest and dedicated test both pass |
| TYPE-05 | 01-01 | Task capability types with convenience constructors (full, tools_only) | SATISFIED | `ServerTaskCapabilities::full()` and `tools_only()` in capabilities.rs; structure matches spec |
| TYPE-06 | 01-01 | TaskGetParams, TaskResultParams, TaskListParams, TaskCancelParams request types match spec schema | SATISFIED | All 5 param types in params.rs with camelCase rename; round-trip tests pass |
| TYPE-07 | 01-01 | TaskStatusNotification type matches spec notification structure | SATISFIED | `TaskStatusNotification` in notification.rs; ttl as required-nullable; 3 unit tests pass |
| TYPE-08 | 01-01 | TaskSupport enum (forbidden/optional/required) with ToolExecution metadata for tools/list | SATISFIED | `TaskSupport` with `#[default]` Forbidden; `ToolExecution` with camelCase taskSupport field |
| TYPE-09 | 01-01 | TaskError variants map to spec-compliant JSON-RPC error codes (-32602, -32603) | SATISFIED | `error_code()` returns -32602 for client errors, -32603 for internal errors; all 8 variants covered |
| TYPE-10 | 01-01 | ModelImmediateResponse meta key constant defined | SATISFIED | `MODEL_IMMEDIATE_RESPONSE_META_KEY = "io.modelcontextprotocol/model-immediate-response"` in constants.rs |
| STOR-01 | 01-02 | TaskStore async trait with create, get, update_status, set_variables, set_result, get_result, list, cancel, cleanup_expired methods | SATISFIED | All 10 async methods plus sync `config()` method in store.rs |
| STOR-02 | 01-02 | TaskStore trait includes atomic `complete_with_result` method | SATISFIED | `complete_with_result` async method with atomicity guarantee documented in doc comment |
| STOR-03 | 01-02 | TaskStore trait enforces configurable variable size limits across all backends | SATISFIED | `StoreConfig` with `max_variable_size_bytes`; `config() -> &StoreConfig` on trait |
| STOR-04 | 01-02 | TaskRecord includes protocol task fields, owner_id, variables, result, and request_method | SATISFIED | `TaskRecord` struct has all 6 required fields plus `expires_at`; all public for store implementors |
| HNDL-01 | 01-02 | TaskWithVariables type extends Task with shared variable store (HashMap<String, Value>) | SATISFIED | `TaskWithVariables { task: Task, variables: HashMap<String, Value> }`; `to_wire_task()` injects into `_meta` |
| TEST-01 | 01-03 | Protocol type serialization tests (all types round-trip correctly) | SATISFIED | 36 integration tests in `tests/protocol_types.rs` covering all wire types |
| TEST-02 | 01-03 | State machine transition tests (valid and invalid transitions, terminal state enforcement) | SATISFIED | 46 integration tests in `tests/state_machine.rs`; exhaustive 5x5 matrix coverage |

**Requirement coverage: 17/17 Phase 1 requirements satisfied**

**Cross-check against REQUIREMENTS.md traceability table:**
- All 17 requirements shown as "Complete" in REQUIREMENTS.md for Phase 1 are verified against actual code
- No orphaned requirements found: every ID in plan frontmatter maps to existing, substantive implementation

---

### Anti-Patterns Found

| File | Line | Pattern | Severity | Impact |
|------|------|---------|----------|--------|
| None | — | — | — | — |

No anti-patterns detected. No TODO/FIXME/placeholder comments, no empty return stubs, no console.log-only implementations, no empty implementations in any source file.

---

### Human Verification Required

None. All phase goal requirements are verifiable programmatically:
- Compilation verified by `cargo check` (exit 0)
- Clippy verified (zero warnings)
- Serialization verified by 36 integration tests
- State machine verified by 46 integration tests
- Property invariants verified by 9 proptest cases
- All requirements traceable from REQUIREMENTS.md to source files

---

### Test Count Summary

| Test Suite | Count | Result |
|-----------|-------|--------|
| Unit tests (inline `#[cfg(test)]`) | 76 | All passed |
| `tests/protocol_types.rs` integration | 36 | All passed |
| `tests/state_machine.rs` integration | 46 | All passed |
| `tests/property_tests.rs` proptest | 9 | All passed |
| Doctests | 33 | All passed |
| **Total** | **200** | **All passed** |

---

### Notable Implementation Details

1. **`_meta` field serialization fix**: `rename_all = "camelCase"` would have converted `_meta` to `"meta"` (strips leading underscore). An explicit `#[serde(rename = "_meta")]` attribute was added to both `Task` and `CreateTaskResult`. This is a real spec-compliance bug that the test suite caught and fixed.

2. **TTL overflow safety**: `TaskRecord::new()` uses `Duration::try_milliseconds` and `checked_add_signed` to prevent panics on extreme TTL values (`u64::MAX`). A proptest fuzz case discovered this.

3. **`TaskError` uses manual Display/Error impls**: The plan specified `thiserror` derive, but manual impls were used instead (identical behavior, more control). This is documented as a known deviation in 01-01-SUMMARY.md.

4. **`TaskStore` has 11 methods, not 10**: Plan 01-02 says "10 methods" in the truth statement but lists 11 in the tasks (including `config()`). The trait correctly has 11: 10 async + 1 sync `config()`.

---

_Verified: 2026-02-21T23:45:00Z_
_Verifier: Claude (gsd-verifier)_
