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

Annotations already declare destructiveHint=true and idempotentHint=false, so the mutating nature is covered. The description adds non-obvious behavior beyond that: admin-only authorization, the prerequisite plan step, and the partial-failure rule that drifted usages are blocked rather than replaced. It stops short of stating whether the source credential is removed or what the response contains.

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 dense sentences, front-loaded with the action and followed by prerequisites and failure semantics. The parenthetical field enumeration is long but functional; nothing is padding.

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 destructive, non-idempotent mutation with no output schema, the description covers permissions, prerequisites, the input contract, and drift handling. Only the post-execution result (what a successful replacement yields, and whether the old credential persists) is left unstated.

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 coverage is 100%, so the schema already documents each field; the baseline is 3. The description earns above baseline by naming the exact nested fields and, more importantly, explaining their provenance and contract ('copied from the plan's eligible_usages', 'pass verbatim'), which is meaning the schema does not convey.

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 precise verb and resource ('swap the selected GitOps usages from a deprecated OAuth credential to a GitHub App credential'), including the direction of the migration. It is clearly distinguishable from the sibling plan_github_credential_replacement, which it names explicitly.

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?

Gives an explicit prerequisite ('Run plan_github_credential_replacement first'), an input contract ('pass its eligible usages verbatim'), an access restriction ('Organisation admins only'), and a routing exclusion for the sibling tool. An agent knows exactly when this tool applies and when a related one does.

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