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

Annotations only declare that this is a non-read-only, closed-world mutation; the description adds the genuinely non-obvious behavioral fact that the tool becomes unavailable once register_plan has run. It does not say whether a partial payload replaces or merges with the existing plan, which matters for a nested-object mutation.

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?

One sentence, front-loaded with the action and immediately followed by the binding constraint in parentheses. Nothing extraneous.

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 mutation with no output schema and a fully documented schema, the key thing an agent needs to know -- that this must happen before registration -- is present. Missing only the merge-vs-replace behavior and what the call returns.

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 description coverage is 100% and every nested plan field carries its own description, so the schema already does the semantic work. The description only confirms that plan and title are the editable surfaces, adding no format or partial-update detail.

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 ("Revise") and resource ("your draft plan or title"), and immediately scopes it against the sibling that ends the window (register_plan). An agent can tell this apart from draft_plan and register_plan without reading the schema.

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?

The exclusion is explicit: only before register_plan is called, after which the plan is locked. It does not spell out the create-then-revise sequence with draft_plan, so the pre-condition is clear but not the full workflow.

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