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

Annotations already declare readOnlyHint=true, so safety is covered, but the description adds genuinely behavioral detail beyond that: secret-bearing fields (tokens, keys) are redacted and the response carries a secret_values_redacted marker. This tells the agent upfront that it cannot retrieve secret material, which is useful for avoiding dead-end workflows.

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?

Two compact sentences, front-loaded with the core action and return contents, then the redaction caveat. Every clause carries information; nothing is padded.

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 no output schema, the description takes on the burden of describing the response: it enumerates the main fields and the redaction marker. For a single-parameter read-only lookup, this is sufficient for an agent to call it and interpret the result.

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%, so credential_id is already documented as a UUID. The description only restates 'by id' and adds no format or lookup-semantics detail beyond the schema, so the baseline 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?

States a specific verb and resource ('Get one credential's details by id') and enumerates the returned facets (identity, provider, availability, dependent clusters/operations). The word 'one' implicitly distinguishes it from list_credentials, so an agent can route correctly 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?

The 'by id' phrasing makes the precondition clear and the singular 'one credential' signals this is the single-item lookup rather than the list tool. It stops short of explicitly naming list_credentials as the alternative or stating when not to use it, so it is clear context without exclusions.

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