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

Annotations already declare readOnly, non-destructive, closed-world, so the safety profile is covered. The description adds real behavioral context: results are user-scoped and carry logged metadata fields (instructions, video_url, image_url, pool_slug). It stops short of mentioning ordering or pagination.

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 short sentences, scope and output content first, filter list second, sibling routing last — well front-loaded. The line 'It holds the ids the user already has' is a slightly cryptic restatement that costs a few words without adding much.

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 not explaining return values is correct; the description instead clarifies scope and the metadata carried through. The remaining gap is filter value semantics, which matters for a zero-coverage 4-param schema but is at least partially implied by the natural-language filter names.

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 0%, so the description must carry the parameters, and it does list all four names plus one real semantic detail (`query` is a substring of name or id). However, it never says what value format `muscle`, `equipment`, or `movement_pattern` accept (slug vs. display name) or whether filters are ANDed, leaving the most error-prone part undocumented.

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 (list) and a precisely scoped resource: THIS USER's own exercise catalog, not the global pool. It also flags the sibling boundary ('new exercises come from search_exercise_pool'), so an agent can pick it without opening the 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?

Gives a clear when-to-use condition (things the user already has/logged) and an explicit alternative for the opposite case (adding new exercises → search_exercise_pool). No statement of when it is the wrong choice beyond that, so it stops short of the full 5.

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