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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds valuable specifics: partial-update semantics ('Only the fields given change') and the mechanism of destruction ('an empty string clears a date or the trail'). It does not detail permission requirements or response shape, keeping it below a 5.

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 tight sentences, no filler, with the scope statement front-loaded and the mutation/clearing semantics following. Every sentence carries distinct information.

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 an 8-parameter mutation tool with no output schema, the description covers the essentials an agent needs: what changes, that changes are partial, how clearing works, and the required edit link. It omits nothing critical, though it could say more about the destructive implications of clearing.

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?

Adds meaning beyond the 63% schema coverage: 'Only the fields given change' documents partial-update behavior, and 'an empty string clears a date or the trail' generalizes the clearing rule that the schema states only per-field. Still leaves unit, title, trail_label and trail_distance_km entirely to the schema.

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 (Sets) and enumerates the resources it modifies (title, display unit, trip dates, trail) on an existing list. The phrase 'on an existing list' implicitly distinguishes it from create_list, but the name 'set_trip' understates the scope (it also sets title, unit, dates).

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?

Usage is implied: 'on an existing list' tells the agent this is an update, not a creation, so create_list is the alternative for new lists. However, no sibling is named explicitly and no when-not-to-use guidance is given, leaving the routing to be inferred.

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