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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, but the description adds useful operational detail: results are capped at 6 choices, copy/share controls are optional, and inputs should be short keywords stripped of personal data. It does not discuss latency, rate limits, or result ranking, so it stops short of full behavioral disclosure.

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 with the routing condition front-loaded, followed by input hygiene and non-capability scoping. Slight redundancy between 'Send only short keywords; omit personal data' and the closing non-capability sentence, but nothing is wasted enough to hurt.

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?

An output schema exists, so return-shape explanation is unnecessary; the description covers selection trigger, alternative tool, input constraints, privacy boundaries, and result count. Nothing an agent needs to invoke this correctly 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 description coverage is 100%, and the schema's query description is already more detailed than the prose (it spells out keyword rules, example queries, and object-carryover behavior). The description's 'search by emotion, character or brief phrase' is directionally consistent but adds little beyond the schema, so baseline 3 applies.

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+resource ('search, browse or compare GIF choices') and explicitly bounds it as reading existing GIFs rather than creating images or sending messages. The sibling tool react_with_gif is named directly, so an agent can disambiguate without opening either schema.

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?

Opens with the precise trigger condition ('when the user explicitly wants to search, browse or compare GIF choices') and routes the alternative case to react_with_gif for the assistant's own conversational response. Also gives negative guidance on what not to include (personal data, transcripts).

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