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

Annotations already flag destructiveHint=true, so the safety profile is partly covered. The description adds an enumeration of mutable fields and the endpoint path, but does not disclose that omissions leave fields unchanged, that some fields are replaced wholesale, or what authorization is required for this mutation.

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 short sentences, front-loaded with the field list; nothing is padded. The trailing endpoint reference is of marginal value to an agent that already knows the tool name, but it is brief enough not to hurt.

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?

All 8 parameters are fully described in the schema and destructiveHint covers the risk profile, so the description is broadly serviceable. However, for a mutation with replace-style fields and identity reassignment, the missing guidance on partial updates versus overwrites leaves a real gap.

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 baseline is 3; the schema already documents every parameter including the milliseconds expiry and the replace semantics of meta/roles/permissions. The description's term "owner" does not match any parameter name (externalId) and adds no syntax or format detail beyond 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?

Names a specific verb (Change) and resource (a key) and enumerates the mutable fields, plus the underlying endpoint POST /v2/keys.updateKey, so the agent knows exactly what the tool does. It does not distinguish itself from the sibling unkey_update_key_credits, which could be confused with a general key update.

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?

No statement of when to use this versus unkey_create_key, unkey_delete_key, or unkey_update_key_credits. The need for an existing keyId is implied by the schema only, and no prerequisites or exclusions are given.

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