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

Annotations already establish this is a non-destructive write in a closed world, so the bar is lower. The description still adds real behavioral context beyond them: the category is inferred from the place unless explicitly supplied, and a note carries the rationale. It stops short of disclosing duplicate handling (re-pinning an existing place) or failure modes, keeping it out of 5 territory.

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?

Two short sentences, no filler. The core action and source tool come first, followed by the optionality/derivation rule, which lets an agent stop reading early if it only needs the basics.

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 an output schema available and annotations covering safety, the description supplies what remains: the source of the place identifier, the purpose of the optional note, and the default category behavior. Nothing essential for a correct invocation is missing, though duplicate-handling behavior would be a nice extra.

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 60%: tripId, placeProviderId and sourceUrl are documented, but note and category are not. The description compensates for exactly those gaps, explaining that note is "why" the place is being pinned and that category is derived from the place unless explicitly provided (matching the enum-override 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 specific verb and resource ("Pins a place ... to the trip's wishlist") and identifies the upstream source tool (search_places), which separates it from get_wishlist, search_places, and planners like add_activity/add_list_item. The collaborative intent ("for the group to vote on") further disambiguates it from the other add_* 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?

Usage is implied rather than stated: placeProviderId must come from search_places, and the "group to vote on" framing hints this is a pre-planning, aspirational step before add_activity. However, there is no explicit when-to-use/when-not guidance versus add_activity or add_list_item, and no prerequisite statement about trip membership.

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