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

Goes well beyond the annotations by disclosing refusal conditions with informative error behavior (empty deliverable, criterion with no proof, non-current step, returned list of what is missing), immutability after closure, the memory side effect ('each closure is also saved as a memory in the plan's project'), and sensitive-content filtering (card numbers, API keys, passwords). These are exactly the traits annotations cannot convey.

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?

Front-loaded with the core action and payload contract, then validation, then side effects and restrictions. Dense but every sentence carries a distinct constraint; the separate closing sentence on sensitive-content refusal is slightly redundant with the earlier refusal sentence.

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 four-required-parameter mutating tool with no output schema and no parameter documentation, the description covers the call contract, failure modes, post-closure behavior, side effects, and downstream workflow. An agent has everything needed to invoke it and handle its results.

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 0%, so the description must carry the load, and it does for the two non-obvious parameters: proofs is one entry per checklist item in checklist order, and deliverable is required and must be non-empty. plan_id and step_id are left implicit, but their meaning is self-evident from the tool's domain.

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 and resource (closes the current plan step) plus the exact payload contract: a deliverable and one proof per checklist item, in checklist order. It distinguishes itself from siblings by naming plan_current_step as the way to discover the step and plan_propose_amendment as the way to fix a closed one.

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?

Explicit routing: use plan_current_step to get the step and its checklist, use this tool only for the current step (any other step is refused), and use plan_propose_amendment to correct an already-closed step. It also states the workflow trigger to stop and ask the user for phase validation.

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