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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description still adds value by disclosing the error behavior for unknown/foreign ids and the non-obvious side effect that a stalled build 'is nudged to continue' — a disclosure an agent would not get from annotations alone, though 'nudged' remains vague about what that write entails.

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 read behavior, then return payload, then routing alternatives — a sensible order. It is dense but every clause carries information; the enumerated return contents run a little long, though they substitute for the missing output schema.

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?

With no output schema, the description carries the return-shape burden and does so (days/stops, bookings, documents, build progress, links, and the 'next' block with budget, stay areas and assistant_hint). Error handling and the build-nudge side effect are also covered, so nothing essential for a correct call 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 coverage is 100% and the schema already documents trip_id with its provenance, so the baseline is 3. The description adds meaning beyond the schema by stating that a trip_id not belonging to this account returns an error, which clarifies the access-scoping semantics of the single parameter.

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 ('Reads one trip') and spells out exactly what the read returns: days and stops in order with item ids, bookings, documents, build progress, open links, plus a 'next' recommendation block. It is clearly distinguished from list_trips and get_menu, so an agent can pick it without opening sibling schemas.

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: 'Use list_trips to find a trip_id, get_menu for what could still be added, open_trip_form to plan a new trip.' It also names the failure precondition (unknown or foreign trip_id returns an error), leaving nothing to inference.

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