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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds real value beyond them by disclosing what each item contains (send/seen/reply counts, attachment_ref) and that search covers transcripts, not just names and descriptions.

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 no filler, front-loading what the tool returns, then search semantics, then the handoff to sibling tools. Each sentence earns its place; the only minor gap is the unmentioned limit/pagination behavior.

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 two-parameter read-only list tool with no output schema, the description covers what items look like (counts, attachment_ref) and how to get the full transcript. It stops short of explaining pagination or the limit default, which is the one thing an agent calling it repeatedly would need.

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 0%, so the description must carry parameter meaning. It explains the search parameter well, including that it matches names, descriptions, and transcripts, but leaves the limit parameter (default 30, max 100) completely undocumented in both schema and description.

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?

The description states the resource precisely: 'Your recorded videos and voice notes with send, seen and reply counts', so an agent knows this returns a library listing rather than messages or contacts. It differentiates from the sibling get_library_item by noting that get_library_item returns the full transcript, though it doesn't explicitly contrast with search_messages or find_attachments.

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?

It gives concrete usage context for the search parameter ('the video where I talk about pricing' works) and names the follow-up tools: attachment_ref for draft_reply and get_library_item for the full transcript. There are no explicit when-not-to-use conditions, but the routing to alternatives is clear.

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