[per-component-executor] - `PhantomMcpTool.Executor` field

[JoshuaRowePhantom]

PhantomMcpTool.Executor field

Part of design: #1432 — per-component-executor-binding
Design document: https://github.com/JoshuaRowePhantom/Phantom.Workspaces/blob/design/docs/design/per-component-executor-binding.md

Scope

Add Executor (nullable string) to PhantomMcpTool using the established recipe: read in PhantomAgentSchema PostProcess (ReadExecutor), copy in From(), emit in Save(). Keep the source-scan guard intact.

Files

Phantom.Workspaces.Llm.Interfaces/PhantomMcpTool.cs; Phantom.Workspaces.Llm.Interfaces/PhantomAgentSchema.cs.

Detailed design

Modified files (applicable):

• Phantom.Workspaces.Llm.Interfaces/PhantomMcpTool.cs — add Executor (nullable string) via the From/Save recipe.
• Phantom.Workspaces.Llm.Interfaces/PhantomAgentSchema.cs — read executor in PostProcess (ReadExecutor) so it survives load.

Verified starting state (evidence):

• PhantomMcpTool : McpTool adds Transport, recovered from dropped JSON props (Phantom.Workspaces.Llm.Interfaces/PhantomMcpTool.cs:34-77) via PhantomAgentSchema.CreateContext PostProcess → ReadTransport (Phantom.Workspaces.Llm.Interfaces/PhantomAgentSchema.cs:47-79), copied in From() and emitted in Save(). A source-scan guard test forbids direct AgentSchema FromJson (enforcing centralisation through PhantomAgentSchema, documented in that file's <remarks>).

Data flow (load / build, applicable part):

1. PhantomAgentSchema.AgentManifestFromJson loads the manifest; PostProcess upgrades each McpTool to PhantomMcpTool, now also recovering the dropped executor field (ReadExecutor).

Tests

PhantomMcpToolExecutorTests (Phantom.Workspaces.Llm.Interfaces.Tests)

• Save_WithExecutor_EmitsExecutorField
• From_CopiesExecutor
• RoundTrip_ExecutorField_Preserved
• (guard) PhantomAgentSchema_IsOnlyLoadEntryPoint_NoDirectFromJson — extend/confirm existing guard.

Testing strategy — PhantomMcpTool.Executor round-trip + guard. Save emits executor, From copies it, a ToJson() → load round-trip preserves it, and the guard test that forbids direct AgentSchema FromJson still passes. → PhantomMcpToolExecutorTests.

Dependencies

None.