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

Annotations only say destructive/idempotent/not-read-only; the description adds substantive behavior: stale or changed revisions are rejected, the key can approve only its own project, provenance is connected-agent rather than verified human, and approval does not activate tracking or authorize live Meta events. This is context an agent cannot get from the annotations.

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 before constraints and exclusions; every sentence carries weight. It is dense across five sentences but none are filler or restatement of the name.

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 tool with no output schema and a fully required nested-parameter set, the description covers preconditions, rejection behavior, authorization scope, and what the action does not do. Nothing an agent needs to call it correctly is missing.

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 0% with a nested object, so the description must carry the load. It explains confirmed: true, the required customer_confirmation scope of approve_plan, and that revision/digest identify an unchanged proposal with stale revisions rejected — a real gain. It stops short of saying the digest is a 64-hex hash of the proposal content, leaving some detail to the schema pattern.

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 precise verb+resource ('Records approval of an unchanged conversion plan proposal') and immediately scopes it against the sibling approve_and_start_conversion_plan with 'Approval only: does not activate tracking or authorize live Meta events.' An agent can select this tool without opening a 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?

Gives explicit preconditions (customer must have explicitly accepted in chat, requires confirmed: true and customer_confirmation with scope approve_plan) and names the alternative path ('The customer can also approve in the signed-in report'). When and when-not are both covered.

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