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

The readOnlyHint annotation already signals a safe read operation dropped the 'grant' clause' — wait, no annotation contradiction. The description adds useful behavioral detail by enumerating the categories of data returned and noting 'where held' (Credential Engine registry identity). It does not disclose error behavior or response shape, but for a read-only fetch this is reasonably transparent.

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?

One long sentence, but every clause enumerates a distinct data facet. It is descriptive without padding, although it front-loads the purpose before listing contents. Slightly dense but well organized.

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?

With one clearly-documented parameter and readOnlyHint annotation, the description sufficiently specifies what data is returned. It does not mention error handling or what happens if the id is invalid, but those are typically not expected in tool descriptions. Overall, adequate for a simple look-up operation.

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?

The input schema provides a full description of the id parameter ('A certification id, copied from a search result's id field'), so schema coverage is 100%. The tool description adds no additional parameter semantics beyond implying the id identifies a single certification. Baseline 3 is appropriate.

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 uses a specific verb phrase ('Everything held about one certification') and enumerates the exact data categories returned, distinguishing it from list/search tools like search_certifications or relationship tools like certifications_for_occupation. It is immediately clear this is a single-record fetch by id.

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 implies it is for retrieving a complete certification record by id, but it never explicitly states when to choose it over siblings like search_certifications or related_certifications. No exclusion or alternative guidance is provided, relying on the tool name and schema (id parameter) to convey usage.

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