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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds genuinely useful behavior beyond annotations: candidates carry id/status/Hook/disclosure class, results are paged, and a miss is a successful empty payload. These details shape an agent's expectations and are not redundant with the annotations.

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 sentences with zero waste. The purpose is front-loaded, followed by the candidate shape and paging, then the empty-payload miss behavior. Every sentence earns its place and no information is repeated from the 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?

Given a rich input schema, an output schema, and safety annotations, the description covers the remaining critical context: when to use the tool, what the results contain, that results are paged, and how a miss behaves. Nothing essential for selecting or invoking the tool 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%, with rich detail for every parameter: kind restrictions, bound range, case-insensitive query matching, cursor reuse, status ladder, and expected_revision semantics. The tool description itself does not explain parameters, but the schema already carries that burden, so the baseline of 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?

The description states a precise action and resource: 'Discover canonical identity from an ordinary-language query.' It further distinguishes itself as 'the entry point when no canonical id is held,' which separates it from siblings like atlas_read that likely operate from a known id. It also concisely summarizes candidate payload fields, paging, and miss behavior.

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?

The description gives a clear usage condition: 'the entry point when no canonical id is held.' This tells an agent when to choose this tool over siblings. However, it does not explicitly name an alternative or state what to do when a canonical id is held, so some inference remains.

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