# Phase 6: Structured Handoff and Client Continuation - Research

**Researched:** 2026-02-22
**Domain:** MCP protocol extension -- handoff message formatting and tool-to-task reconnection
**Confidence:** HIGH

## Summary

Phase 6 adds two capabilities to the task-aware workflow system: (1) a structured handoff message appended to the `GetPromptResult` when execution pauses partway through, and (2) a reconnection path where follow-up `tools/call` requests with `_task_id` in `_meta` update the workflow's task variables and progress. Both capabilities build directly on the Phase 5 active execution engine (`TaskWorkflowPromptHandler`) and the existing task infrastructure (`TaskRouter`, `TaskStore`, `_meta` on `GetPromptResult`).

The handoff is a final assistant message in the `messages` vec that narrates what happened and what the client should do next, complemented by the lean `_meta` JSON already emitted by Phase 5. The continuation path requires intercepting `tools/call` requests in `ServerCore` when `_meta._task_id` is present, matching the tool to a remaining workflow step, storing the result in task variables, and updating progress. The client signals explicit completion via the existing `tasks/cancel` endpoint (repurposed with a result value, per user decision). No new MCP endpoints are required.

**Primary recommendation:** Implement handoff as a message-generation function in `TaskWorkflowPromptHandler`, and continuation as a new `TaskRouter` method + `ServerCore` intercept, keeping the architecture within the existing composition pattern.

<user_constraints>
## User Constraints (from CONTEXT.md)

### Locked Decisions
- Primary audience is LLM clients (Claude, GPT) -- optimize for LLM comprehension
- The message list follows the MCP prompt spec format: conversation trace of user/assistant messages that mirror what the interaction would look like if the client was actually making the planned calls
- When execution pauses, add an assistant message that naturally continues the conversation: "Step 2 failed because X. To continue, call deploy_service with {region: us-east-1}. Then call notify_team with..."
- _meta on GetPromptResult stays lean for the initial prompt -- task_id and task_status. The message list carries the details (step results already appear as tool-call/result message pairs)
- Completed steps are already visible in the conversation trace as tool call announcements + tool result messages -- no need to re-summarize them in the handoff
- Each remaining step in the handoff includes: tool name, pre-resolved argument values (where available), and guidance text
- When args can't be fully resolved (depend on output from a step the client needs to run first), use explicit placeholders: "Call notify_team with {result: <output from deploy_service>}"
- When a step has a guidance field defined, include it in the handoff narrative for reasoning context
- Task ID is only in _meta, NOT mentioned in the narrative text
- The workflow plan is guidance, not enforcement -- the LLM client can call any tool in any order with any arguments. The server does NOT validate or block based on step ordering
- When a tool call includes `_task_id` in `_meta` and the tool matches a remaining workflow step, mark that step as completed and store the result under `_workflow.result.<step_name>` (best-effort matching, no blocking)
- When the tool does NOT match any workflow step, record the result under a generic key like `_workflow.extra.<tool_name>` for observability
- Retries: last result wins (overwrite). If the client calls the same step tool twice, the latest result replaces the previous one
- Progress tracking is updated in task variables after each reconnected tool call
- Auto-complete ONLY during initial prompt execution (when all steps succeed in the server-side loop)
- During client continuation, the task stays Working even if all steps are marked completed -- explicit completion required
- Client signals completion via existing `tasks/cancel` with a completed result -- reuse existing task API infrastructure, no new endpoint
- `tasks/result` polling behavior is Claude's discretion (standard task record with variables already includes `_workflow.*` data)

### Claude's Discretion
- Exact `tasks/result` response formatting (whether to add workflow-specific formatting or rely on standard task variables)
- Internal data structures for step matching during reconnection
- Error response format when `_task_id` references a non-existent or already-completed task
- How to handle edge cases like tool calls after task is already completed

### Deferred Ideas (OUT OF SCOPE)
- Resume-from-task (re-invoke prompt with task ID to continue from last completed step) -- v2 ADVW-02
- DataSource::TaskVariable for reading values from task variable store -- v2 ADVW-01
- Builder API wiring for task-aware workflows -- Phase 7 INTG-01
</user_constraints>

<phase_requirements>
## Phase Requirements

| ID | Description | Research Support |
|----|-------------|-----------------|
| HAND-01 | Prompt reply includes structured handoff as final assistant message with task ID, completed steps with results, and remaining steps with guidance | Handoff message generation pattern (Section: Architecture Patterns > Handoff Message Generation). Task ID is in `_meta` only, not in the narrative per locked decision. Completed steps are already visible as tool-call/result message pairs. |
| HAND-02 | Handoff format is hybrid: JSON block for machine parsing plus natural language for LLM clients | `_meta` on `GetPromptResult` already provides JSON (Phase 5). The final assistant message is the natural language component. Together they form the hybrid format. |
| HAND-03 | Each remaining step in handoff includes tool name, expected arguments (with resolved values where available), and guidance text | Argument resolution using `resolve_tool_parameters` for resolvable steps and placeholder syntax for unresolvable ones. Guidance from `WorkflowStep.guidance()`. |
| CONT-01 | Follow-up tool calls can reference the workflow task via _task_id in request _meta | `RequestMeta` needs `_task_id` field OR `ServerCore` extracts it from the raw `_meta` JSON. Intercept in `handle_call_tool` or `handle_request_internal`. |
| CONT-02 | Task variables are updated with step results when tool calls include _task_id binding | New `TaskRouter` method `handle_workflow_tool_call` that matches tool name to step, updates `_workflow.result.<step_name>` and `_workflow.progress`. |
| CONT-03 | Client can poll tasks/result to check overall workflow completion status | Already supported: `tasks/result` returns task variables via `to_wire_task_with_variables()`. Client completes task via `tasks/cancel` with result (new: extend `TaskCancelParams` or use `complete_workflow_task` through a new router method). |
</phase_requirements>

## Standard Stack

### Core
| Library | Version | Purpose | Why Standard |
|---------|---------|---------|--------------|
| pmcp | 1.10.x | Core MCP SDK with `GetPromptResult`, `PromptMessage`, `Role`, `RequestMeta` | This is the project itself |
| pmcp-tasks | workspace | Task lifecycle, `TaskRouter`, `TaskStore`, workflow types | This is the project's task crate |
| serde_json | 1.x | JSON value construction for `_meta`, handoff message, variable updates | Already a core dependency |
| async_trait | 0.1.x | Async trait definitions for `TaskRouter` methods | Already used throughout |

### Supporting
| Library | Version | Purpose | When to Use |
|---------|---------|---------|-------------|
| indexmap | 2.x | Deterministic step ordering in workflow definitions | Already used in `SequentialWorkflow` |
| tracing | 0.1.x | Structured logging for continuation intercept points | Already used throughout |

### Alternatives Considered
| Instead of | Could Use | Tradeoff |
|------------|-----------|----------|
| Raw string formatting for handoff | Tera/Handlebars template engine | Over-engineering for structured text; `format!()` and string building is sufficient for the conversation narrative |
| New `tasks/complete` endpoint | Existing `tasks/cancel` with extended params | User decision locks reuse of `tasks/cancel`; avoids new endpoint |

**No additional dependencies needed.** All required functionality is already available in the workspace.

## Architecture Patterns

### Recommended File Structure
```
src/server/workflow/
    task_prompt_handler.rs   # MODIFY: add handoff message generation
    mod.rs                   # No changes needed
src/server/
    core.rs                  # MODIFY: add _task_id intercept in handle_call_tool
    tasks.rs                 # MODIFY: add handle_workflow_continuation method to TaskRouter
src/types/
    protocol.rs              # INSPECT: may need _task_id awareness in RequestMeta (or extract from raw JSON)
crates/pmcp-tasks/src/
    router.rs                # MODIFY: implement handle_workflow_continuation
    types/params.rs          # MODIFY: extend TaskCancelParams for completion-with-result
    types/workflow.rs        # MODIFY: add WORKFLOW_EXTRA_PREFIX constant
```

### Pattern 1: Handoff Message Generation
**What:** A method on `TaskWorkflowPromptHandler` that builds the final assistant message narrating remaining steps with tool names, resolved args, placeholders, and guidance.
**When to use:** Called at the end of the execution loop when `pause_reason.is_some()` (i.e., execution did not complete all steps).

**Key design points:**
- The handoff message is a single `PromptMessage` with `Role::Assistant` appended to the existing `messages` vec
- It does NOT repeat completed step results (they are already in the conversation trace as tool-call/tool-result message pairs)
- It iterates remaining steps (those with `StepStatus::Pending`) and for each:
  - Calls `resolve_tool_parameters()` to get pre-resolved args where possible
  - Falls back to placeholder syntax `<output from {step_name}>` for unresolvable args
  - Includes `step.guidance()` text if present
- Task ID is NOT mentioned in the narrative (it is only in `_meta`)

**Example output:**
```
Step 2 failed: connection timeout calling deploy_service. This step is retryable.

To continue the workflow, make these tool calls:

1. Call deploy_service with {"region": "us-east-1", "config": {"valid": true}}
   Note: Retry the deployment with the validated configuration.

2. Call notify_team with {"result": <output from deploy_service>, "channel": "#ops"}
   Note: Notify the team once deployment completes.
```

### Pattern 2: Tool-to-Task Reconnection Intercept
**What:** When `ServerCore` receives a `tools/call` with `_task_id` in `_meta`, it executes the tool normally, then notifies the task router to record the result against the workflow.
**When to use:** Every `tools/call` that includes `_meta._task_id`.

**Key design points:**
- `ServerCore.handle_call_tool` already processes `_meta` for progress tokens (line 744)
- Add a parallel check: if `_meta` contains a `_task_id` string, extract it
- Execute the tool call normally (existing path -- all middleware, auth, etc. applies)
- After successful execution, call a new `TaskRouter::handle_workflow_continuation()` method
- The continuation method:
  1. Loads the task to verify it exists and is Working
  2. Loads `_workflow.progress` from task variables
  3. Matches `tool_name` against remaining step `tool` fields (best-effort)
  4. If matched: sets `_workflow.result.<step_name>` and updates step status in progress
  5. If not matched: sets `_workflow.extra.<tool_name>` for observability
  6. Writes updated progress back to task variables
- This is fire-and-forget from the tool call perspective -- the tool result is returned to the client regardless of whether the continuation recording succeeds

### Pattern 3: Completion via tasks/cancel
**What:** Client signals workflow completion by calling `tasks/cancel` with an optional result payload.
**When to use:** After the client has executed all remaining steps and wants to mark the workflow as done.

**Key design points:**
- Extend `TaskCancelParams` with an optional `result` field
- When `result` is present, use `complete_with_result(task_id, owner_id, TaskStatus::Completed, None, result)` instead of `cancel()`
- This repurposes `tasks/cancel` as a dual-purpose endpoint: cancel (without result) or complete (with result)
- The router's `handle_tasks_cancel` method needs to branch on presence of `result`

**Alternative approach (recommended):** Instead of extending `TaskCancelParams`, add a new `TaskRouter` method `complete_workflow_from_client()` and route to it when the cancel params include a result. This keeps the cancel semantics clean while enabling the completion path.

### Anti-Patterns to Avoid
- **Re-summarizing completed steps in the handoff:** The completed steps are already visible in the conversation trace as tool-call announcement (assistant) + tool result (user) message pairs. Re-summarizing duplicates information and wastes tokens. The handoff only covers remaining steps.
- **Mentioning task_id in the narrative text:** Task ID belongs in `_meta` for machine parsing. LLM clients do not need it in the narrative. Including it clutters the natural language and creates a coupling between the narrative and the structured data.
- **Blocking tool calls based on step ordering:** The server MUST NOT validate or reject tool calls based on whether they match the expected workflow step order. The LLM client is intelligent and may choose a different order.
- **Auto-completing during continuation:** Auto-complete only during the initial prompt execution (Phase 5). During client continuation, the task stays Working even if all steps are marked completed. Only explicit completion via `tasks/cancel`-with-result transitions to Completed.
- **Modifying WorkflowPromptHandler:** All changes go in `TaskWorkflowPromptHandler` (composition pattern, not modification).

## Don't Hand-Roll

| Problem | Don't Build | Use Instead | Why |
|---------|-------------|-------------|-----|
| Tool parameter resolution | Custom resolution logic | `WorkflowPromptHandler::resolve_tool_parameters()` | Already handles PromptArg, StepOutput, Constant, Field data sources with proper error handling |
| Step matching by tool name | Complex step graph matcher | Simple linear scan of `_workflow.progress.steps` | Sequential workflow -- linear scan is correct and efficient for 2-10 steps |
| Task variable persistence | Custom persistence logic | `TaskRouter::set_task_variables()` | Already handles batch writes with proper error conversion |
| Tool execution with middleware | Direct tool handler call | Existing `handle_call_tool` path in `ServerCore` | Ensures OAuth, logging, authorization middleware all apply |

**Key insight:** The Phase 5 codebase already provides all the building blocks. Phase 6 is primarily composition -- wiring existing components together in new ways (handoff message, intercept path) rather than building new infrastructure.

## Common Pitfalls

### Pitfall 1: Handoff Message Repeating Completed Steps
**What goes wrong:** The handoff message re-lists completed steps with their results, duplicating what is already in the conversation trace.
**Why it happens:** Natural instinct to provide a "complete summary" in the handoff.
**How to avoid:** The locked decision explicitly states "Completed steps are already visible in the conversation trace as tool call announcements + tool result messages -- no need to re-summarize them in the handoff." Only include remaining steps.
**Warning signs:** Handoff message contains "Step 1 (completed): validate_config returned {valid: true}" -- this is already in the messages vec.

### Pitfall 2: _task_id Extraction from Nested _meta
**What goes wrong:** `RequestMeta` struct only has `progress_token` field. `_task_id` is not a typed field.
**Why it happens:** `RequestMeta` is defined for the MCP spec's standard `_meta` fields. `_task_id` is a PMCP extension.
**How to avoid:** Either (a) add `_task_id` as an optional field on `RequestMeta` with `#[serde(flatten)]` for additional fields, or (b) parse `_task_id` from the raw JSON `_meta` map in `ServerCore` before it is deserialized into `RequestMeta`. Option (b) is cleaner since it avoids modifying the core protocol type.
**Warning signs:** `_task_id` silently dropped during deserialization because `RequestMeta` does not have the field.

### Pitfall 3: Race Condition in Continuation Variable Updates
**What goes wrong:** Two concurrent tool calls with the same `_task_id` both try to update `_workflow.progress` and one overwrites the other's step completion.
**Why it happens:** Read-modify-write on `_workflow.progress` is not atomic.
**How to avoid:** The locked decision says "retries: last result wins (overwrite)" -- so this is acceptable behavior for retries. For genuinely concurrent step calls, the `InMemoryTaskStore` uses DashMap entry locks which serialize writes. The `_workflow.progress` update should be done as a single `set_variables` call that includes both the step result and the updated progress.
**Warning signs:** Step status flipping between `completed` and `pending` in task variables.

### Pitfall 4: Circular Dependency When Adding Workflow Methods to TaskRouter
**What goes wrong:** Adding methods to `TaskRouter` (in `pmcp`) that reference types from `pmcp-tasks` creates a circular dependency.
**Why it happens:** `pmcp-tasks` depends on `pmcp`. `pmcp` cannot depend on `pmcp-tasks`.
**How to avoid:** All new `TaskRouter` methods must use `serde_json::Value` parameters and return types (same pattern as existing methods). Type-safe parsing happens inside the `pmcp-tasks` implementation.
**Warning signs:** Compiler error about circular crate dependencies.

### Pitfall 5: Client Completion via tasks/cancel Conflating Semantics
**What goes wrong:** Using `tasks/cancel` for both "cancel the task" and "complete the task with a result" creates confusing API semantics.
**Why it happens:** User decision to reuse existing endpoint rather than adding a new one.
**How to avoid:** Make the branching logic clear: if `TaskCancelParams` includes a `result` field, treat it as completion (not cancellation). Document this dual behavior clearly. Consider naming the extended params or the router method to make intent clear (e.g., `handle_tasks_cancel_or_complete`).
**Warning signs:** Cancelled tasks appearing with `Completed` status, or completed tasks with `Cancelled` status.

### Pitfall 6: Handoff Argument Resolution Failing on Steps With Missing Dependencies
**What goes wrong:** Calling `resolve_tool_parameters()` for a remaining step that depends on a step the client has not yet executed causes a panic or error.
**Why it happens:** The resolution function expects step output bindings to be in the `ExecutionContext`, but for remaining steps, those bindings do not exist.
**How to avoid:** For the handoff, attempt resolution and on failure, use placeholder syntax: `<output from {binding_name}>`. The `resolve_tool_parameters` method already returns `Err` on missing bindings -- catch this and substitute placeholders.
**Warning signs:** Handoff generation panicking or returning an error instead of a graceful placeholder.

## Code Examples

### Handoff Message Generation (Pseudocode)
```rust
// Source: Derived from existing task_prompt_handler.rs patterns
fn build_handoff_message(
    &self,
    step_statuses: &[StepStatus],
    step_results: &[(String, Value)],
    pause_reason: &PauseReason,
    args: &HashMap<String, String>,
    execution_context: &ExecutionContext,
) -> PromptMessage {
    let mut text = String::new();

    // Describe what happened (pause reason)
    match pause_reason {
        PauseReason::ToolError { failed_step, error, retryable, .. } => {
            text.push_str(&format!(
                "Step '{}' failed: {}.",
                failed_step, error
            ));
            if *retryable {
                text.push_str(" This step is retryable.");
            }
        }
        PauseReason::UnresolvableParams { blocked_step, missing_param, .. } => {
            text.push_str(&format!(
                "I could not resolve parameter '{}' for step '{}'.",
                missing_param, blocked_step
            ));
        }
        // ... other variants
    }

    text.push_str("\n\nTo continue the workflow, make these tool calls:\n\n");

    // List remaining steps
    let mut step_num = 1;
    for (idx, step) in self.workflow.steps().iter().enumerate() {
        if step_statuses[idx] != StepStatus::Pending {
            continue;
        }
        let tool_name = step.tool()
            .map(|t| t.name().to_string())
            .unwrap_or_else(|| "unknown".to_string());

        // Attempt to resolve args
        let args_str = match self.inner.resolve_tool_parameters(step, args, execution_context) {
            Ok(resolved) => serde_json::to_string(&resolved)
                .unwrap_or_else(|_| "{}".to_string()),
            Err(_) => {
                // Build placeholder args
                self.build_placeholder_args(step, execution_context)
            }
        };

        text.push_str(&format!("{}. Call {} with {}\n", step_num, tool_name, args_str));

        // Include guidance if present
        if let Some(guidance) = step.guidance() {
            let guidance_text = WorkflowPromptHandler::substitute_arguments(guidance, args);
            text.push_str(&format!("   Note: {}\n", guidance_text));
        }

        text.push('\n');
        step_num += 1;
    }

    PromptMessage {
        role: Role::Assistant,
        content: MessageContent::Text { text },
    }
}
```

### Tool-to-Task Reconnection in ServerCore (Pseudocode)
```rust
// Source: Derived from existing ServerCore::handle_request_internal patterns
// In handle_call_tool or handle_request_internal, after normal tool execution:

// Extract _task_id from _meta if present
let task_id = req._meta.as_ref()
    .and_then(|m| m.get("_task_id"))  // If using raw JSON access
    .and_then(|v| v.as_str())
    .map(String::from);

// Execute tool normally (existing path)
let tool_result = self.handle_call_tool(req, auth_context.clone()).await?;

// If _task_id present, fire-and-forget continuation recording
if let (Some(task_id), Some(ref task_router)) = (task_id, &self.task_router) {
    let owner_id = self.resolve_task_owner(&auth_context)
        .unwrap_or_else(|| "local".to_string());

    // Best-effort: don't fail the tool call if continuation recording fails
    if let Err(e) = task_router.handle_workflow_continuation(
        &task_id,
        &req.name,
        serde_json::to_value(&tool_result).unwrap_or_default(),
        &owner_id,
    ).await {
        tracing::warn!(
            "Workflow continuation recording failed for task {}: {}",
            task_id, e
        );
    }
}
```

### New TaskRouter Method Signature
```rust
// Source: Following existing TaskRouter patterns in src/server/tasks.rs

/// Record a tool call result against a workflow task.
///
/// Called by `ServerCore` when a `tools/call` includes `_task_id` in `_meta`.
/// The implementation matches the tool name to a remaining workflow step
/// and updates task variables with the step result and updated progress.
///
/// Best-effort: if the tool does not match any step, the result is stored
/// under `_workflow.extra.<tool_name>` for observability.
///
/// # Default
///
/// Returns Ok(()) -- no-op for routers that don't support workflow continuation.
async fn handle_workflow_continuation(
    &self,
    _task_id: &str,
    _tool_name: &str,
    _tool_result: Value,
    _owner_id: &str,
) -> Result<()> {
    Ok(())
}
```

### Completion via tasks/cancel with Result
```rust
// Source: Extending existing TaskCancelParams

/// Extended parameters for `tasks/cancel` requests.
/// When `result` is present, the task is completed (not cancelled).
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct TaskCancelParams {
    /// The task ID to cancel or complete.
    pub task_id: String,
    /// Optional result value. When present, completes the task
    /// instead of cancelling it. Used by workflow clients to signal
    /// explicit completion after executing remaining steps.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub result: Option<Value>,
}
```

## State of the Art

| Old Approach | Current Approach | When Changed | Impact |
|--------------|------------------|--------------|--------|
| StepExecution enum (server vs client steps) | Runtime best-effort execution (all steps attempted) | Phase 4 (FNDX-02 dropped) | Handoff only occurs when runtime execution pauses, not at pre-classified client steps |
| Separate `_meta` for each message | Single `_meta` on `GetPromptResult` + narrative in messages | Phase 5 | Handoff is the narrative message, `_meta` is the machine-readable companion |

**Deprecated/outdated:**
- StepExecution enum: Dropped in Phase 4. All steps execute best-effort at runtime. The handoff occurs when execution pauses for any reason (PauseReason).
- "Client-deferred steps" terminology: No longer meaningful. All steps are attempted by the server; the client picks up from wherever execution paused.

## Open Questions

1. **How to handle `_task_id` deserialization in RequestMeta**
   - What we know: `RequestMeta` currently only has `progress_token`. Adding `_task_id` as a typed field would be the cleanest approach but modifies a core protocol type.
   - What's unclear: Whether to use `#[serde(flatten)]` to capture extra fields, or extract `_task_id` from the raw JSON before `RequestMeta` deserialization.
   - Recommendation: Add `_task_id` as an optional field with `#[serde(skip_serializing_if = "Option::is_none")]` on `RequestMeta`. This is consistent with `progress_token` being there, and `_task_id` is a PMCP extension that belongs in request metadata. The `#[allow(clippy::pub_underscore_fields)]` attribute is already used for `_meta`.

2. **tasks/cancel with result -- implementation approach**
   - What we know: User decided to reuse `tasks/cancel` for client-triggered completion. Current `TaskCancelParams` only has `task_id`.
   - What's unclear: Whether to extend `TaskCancelParams` directly or use a separate code path when result is present.
   - Recommendation: Extend `TaskCancelParams` with an optional `result` field. In the router's `handle_tasks_cancel`, branch: if `result` is present, call `complete_with_result()` with `TaskStatus::Completed`; otherwise, call `cancel()` as today. This is backward-compatible (existing cancel calls without result field still work).

3. **tasks/result response formatting for workflows**
   - What we know: `tasks/result` currently returns `{ result: Value, _meta: { io.modelcontextprotocol/related-task: ... } }`. For workflows, the task variables contain `_workflow.progress`, `_workflow.result.*`, etc.
   - What's unclear: Whether `tasks/result` should surface workflow-specific formatting or just return the standard task data.
   - Recommendation: Rely on standard task variables. The client can poll `tasks/get` which returns the full task with variables including all `_workflow.*` entries. `tasks/result` already works for completed workflows since `complete_workflow_task` stores a result. No special formatting needed -- this is the simplest approach and consistent with the principle that `_workflow.*` variables are the source of truth.

## Sources

### Primary (HIGH confidence)
- **Codebase inspection** -- `src/server/workflow/task_prompt_handler.rs` (1161 lines), `src/server/core.rs` (878 lines), `src/server/tasks.rs` (164 lines), `crates/pmcp-tasks/src/router.rs` (887 lines), `crates/pmcp-tasks/src/types/workflow.rs` (767 lines), `src/types/protocol.rs` (GetPromptResult, RequestMeta, CallToolRequest definitions)
- **MCP Prompts Specification** -- https://modelcontextprotocol.io/specification/2025-06-18/server/prompts -- confirmed PromptMessage format (role + content), GetPromptResult structure, text content type
- **Phase 5 Verification Report** -- `.planning/phases/05-partial-execution-engine/05-VERIFICATION.md` -- confirmed all Phase 5 requirements satisfied, execution engine working

### Secondary (MEDIUM confidence)
- **CONTEXT.md decisions** -- All implementation decisions locked by user in Phase 6 context discussion

### Tertiary (LOW confidence)
- None -- all findings verified against actual codebase

## Metadata

**Confidence breakdown:**
- Standard stack: HIGH -- all libraries already in workspace, no new dependencies
- Architecture: HIGH -- patterns directly extend existing Phase 5 code with clear insertion points identified in `task_prompt_handler.rs`, `core.rs`, `tasks.rs`, and `router.rs`
- Pitfalls: HIGH -- identified through direct codebase analysis of type structures, data flow, and composition patterns

**Research date:** 2026-02-22
**Valid until:** 2026-03-22 (stable internal architecture, no external dependency changes)
