Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructive/non-idempotent/openWorld, but the description goes well beyond them: it specifies the required signed auth headers, session-token fallback, the wall-update precondition that gates the run, and the exact 409 error. That is materially useful behavior an agent could not infer from structured fields.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose and usage lead, then preconditions, then auth/transport. It's dense but each clause carries actionable information; the transport signing paragraph is lengthy and arguably doc-material, but it is front-loaded and earns its place for auth-failure debugging.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a non-idempotent, destructive, no-output-schema tool, the description covers auth, preconditions, error codes, and transports. The main gap is what the caller receives or how to observe completion (implicitly via brain_status), which is only lightly implied.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% across all three parameters, so the schema already carries parameter meaning. The description adds only incidental context (the task:<id> wall scope) and no extra semantics for context or agent_id, making the 3 baseline appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb chain and resource: the brain reads a task, generates a deliverable, and submits the result. This clearly differentiates it from siblings like brain_status (poll) and brain_complete (likely closeout), so an agent can route correctly without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives explicit triggering conditions: the assigned agent's harness is down, or a user wants to drive a task remotely. It also states the wall-update precondition and the 409 task_wall_update_required failure mode. It doesn't name sibling alternatives (e.g. brain_status for polling), so it stops short of 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.