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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true; the description adds the useful clarification 'Does not change schedule data', which tells the agent the scope of side effects is limited. However, 'bind' implies persisted state and the description never explains what is written where, who is authorized, or what happens on repeat calls, so it goes only slightly past 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?

Three short, front-loaded sentences with no filler. Each carries a distinct fact (app-only, precondition, side-effect scope), though the phrasing is clipped enough to be cryptic.

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 tool with two required, fully undocumented parameters, an open-world hint, and no output schema, the description leaves too much unspecified: it does not say what a plan is, what the call returns, or what happens if participant_id is unknown. The safety scope note helps, but the call cannot be made confidently from this text plus the schema.

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% and both parameters (plan, participant_id) are required but undocumented. The description only alludes to a 'name' being selected and never explains what a plan identifier is or how participant_id relates to the selected name, so it fails to compensate for the coverage gap.

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?

The description names the resource ('identity picker', 'the name explicitly selected') and scopes it as app-only, so the general intent is graspable. But it is phrased as a noun phrase plus the vague verb 'bind', so it never states concretely what operation is performed on the participant, and it does not differentiate itself from the sibling widget_lookup/widget_write tools.

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?

'App-only' and 'the name explicitly selected in the shared web UI' imply a precondition: call this only in the app after a name was picked in the web UI. There is no explicit when-not guidance, no mention of widget_lookup or widget_write as alternatives, and no statement about what to do if no selection exists.

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