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

Annotations already declare read-only/idempotent/non-destructive, but the description adds behavior they cannot express: the total/pages values shift with the category filter, the filter and per_page must stay constant across pages or paging desynchronizes, entries are summaries rather than full records, and a bulk-mirror endpoint exists. That is substantive operational context beyond the annotation set.

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?

Front-loads purpose and the use/don't-use split, then layers paging mechanics and an escape hatch. Dense but nearly every clause carries information; the NDJSON mirror sentence is the one optional add-on, and the 'Returns {...}' shape listing is partly redundant given the output schema.

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 paginated, filterable list tool with an output schema already present, the description covers paging loop termination, filter/per_page stability, summary-vs-full-record expectations, sibling routing, and a bulk alternative. Nothing an agent needs to call it 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 coverage is 100%, so the baseline is 3, but the description adds cross-parameter invariants the per-field schema text only states in isolation: keep the category filter identical across pages, keep per_page constant, and stop at the 'pages' value from the first response. It is mostly reinforcement of the schema rather than new per-parameter meaning, hence not a 5.

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 ('Enumerate the whole approved catalogue') plus the ordering guarantee ('deterministic slug order, page by page'). It also explicitly contrasts itself with the specific-lookup path, so an agent can separate it from search_registry or discover_capabilities without opening a 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 the when ('you want everything — mirroring, auditing, building your own index'), the when-not ('not when you are looking for something specific'), and routes to three named alternatives by intent: search_registry for keyword, discover_capabilities for plain-language needs, list_categories for valid category values. Near-exhaustive routing guidance.

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