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

Annotations already declare destructiveHint=true and readOnlyHint=false, covering the safety profile, so the description's job here is lighter. It adds useful context that credentials are label-keyed and that custom login-based auth is supported, but it does not clarify that list is non-mutating while delete is irreversible, nor what permissions or spec state are required.

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 with the action set front-loaded and no filler. It is well-sized, though the trailing auth sentence is thinner than the nested schema it gestures at.

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 four-action tool over a complex nested auth object with no output schema, the description is adequate but shallow: it never explains what each action returns or requires beyond the schema. The rich 100%-covered schema carries most of the load, keeping this at minimum viable rather than incomplete.

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 the schema already documents every parameter, setting the baseline at 3. The description adds modest value by giving label examples ('default', 'admin') and flagging custom auth support, but it says nothing about the many nested auth fields (tokenUrl, selectors, tokenPrefix, etc.) that dominate the schema.

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 names specific verbs (list, save, update, delete) and a specific resource (credentials for a spec), which is clear enough to distinguish it from all siblings, none of which touch credentials. It loses the top score only because it bundles four operations without indicating priorities or defaults.

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?

Usage is implied by the four enumerated actions and the requirement of a specId, but there is no explicit when-to-use/when-not guidance, no statement of prerequisites (e.g. that a spec must exist first), and no routing to or away from any sibling. This is minimum viable, not instructive.

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