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

Annotations give readOnlyHint=false and destructiveHint=false without explaining why; the description resolves this by disclosing the actual side effect (a note saved to the person's Autonomad thread) while confirming no booking is changed and nothing is passed on. It also covers auth requirements and the first-use permission prompt, which annotations cannot express.

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 non-mutation guarantee, then per-type behavior, then follow-up routing, then side effects and auth. It is dense rather than padded, though a few clauses (repeated 'no booking is changed', 'nothing is passed on') restate the same promise twice.

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 preview tool with no output schema, the description tells the agent what comes back for each type (cancelable parts and terms for cancel; what would go to the concierge for rebook/modify) and what to do with it. Auth, side effects, and a stated limitation complete the picture.

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 already 100%, so baseline is 3; the description adds real value by tying type values to outcome behavior and by telling the agent to reuse 'the same reference' on the follow-up call. It does not elaborate on details' 4000-char limit or component_ids sourcing beyond the schema's own note.

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 ('shows ... what a booking change would do') and immediately scopes it as non-mutating. It then breaks the meaning down per enum value (cancel vs rebook/modify), which no sibling tool description would supply.

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?

Explicitly routes the agent: show the result to the person, and if they agree call cancel_booking for cancel or request_booking_change for rebook/modify 'with the same reference'. It also states the precondition it does NOT check (whether the trip has Trip Concierge), preventing a wrong assumption.

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