Architectural Context
When attempting to use replace or write_file tools on paths within .agent/skills/, the tools return success messages (e.g., "successfully updated"), but the changes are not persisted to the local disk. Bash tools (cp, touch) work correctly in these directories.
The Problem
This appears to be a harness guardrail designed to prevent autonomous agents from modifying their own instructions and skill logic through standard tool flow. The intent of this security boundary is sound. However, the implementation violates the core tool contract: it fails silently. Returning a simulated success when the operation was actively blocked causes agents to waste multiple cycles attempting to read back state that was never written, degrading efficiency and context.
Avoided Traps
- Do not bypass the guardrail: The security perimeter around
.agent/skills/ is valid and should remain.
- Do not use bash as a primary solution: Agents currently work around this by writing to
/tmp/ and using cp, but the primary MCP tool must be reliable.
Prescription
The tool implementation or harness interceptor must be modified to make this failure mode loud. If a write is blocked due to path restrictions, the tool MUST return an explicit error (e.g., Error: Write blocked by harness guardrail) instead of simulating success.
Origin Session ID: 0b29a8fa-c6b0-42e2-ab3b-8015a99db2d8
Architectural Context
When attempting to use
replaceorwrite_filetools on paths within.agent/skills/, the tools return success messages (e.g., "successfully updated"), but the changes are not persisted to the local disk. Bash tools (cp,touch) work correctly in these directories.The Problem
This appears to be a harness guardrail designed to prevent autonomous agents from modifying their own instructions and skill logic through standard tool flow. The intent of this security boundary is sound. However, the implementation violates the core tool contract: it fails silently. Returning a simulated success when the operation was actively blocked causes agents to waste multiple cycles attempting to read back state that was never written, degrading efficiency and context.
Avoided Traps
.agent/skills/is valid and should remain./tmp/and usingcp, but the primary MCP tool must be reliable.Prescription
The tool implementation or harness interceptor must be modified to make this failure mode loud. If a write is blocked due to path restrictions, the tool MUST return an explicit error (e.g.,
Error: Write blocked by harness guardrail) instead of simulating success.Origin Session ID:
0b29a8fa-c6b0-42e2-ab3b-8015a99db2d8