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

The annotations already establish read-only and idempotent behavior, but the description adds substantial context beyond them: it is free, pattern-based only, never echoes matched values, returns structured findings, and handles invalid input with an error object rather than a protocol error. It also states that retrying after correction is safe.

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?

The description is front-loaded with the core action and target, and nearly every sentence adds useful behavioral context. It is slightly long for a one-parameter scanner and includes a return-value sketch even though an output schema exists, but it avoids filler and remains 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?

For a simple one-parameter scanner, the description covers the key gaps an agent would otherwise have: limitations of pattern matching, human-confirmation requirement, no echoing of secrets, error behavior, and retry safety. With annotations and an output schema present, this is complete enough to invoke correctly.

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% and there is only one parameter, so the schema already explains that `text` is the file, diff, or config contents pasted as a single string. The description repeats that usage with a typical input example, but adds no further constraints or format details 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?

The description uses a specific verb, 'Scan', and names the exact resource and targets: text containing accidentally-committed machine credentials and private-key material. It also distinguishes the tool from the broader sibling `security_deep_dive` by explicitly saying it is not a general security review.

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?

It gives clear usage context: scanning file, diff, or config contents for leaked credentials. It explicitly routes broader security work away from this tool by naming `security_deep_dive`, and it explains the trust boundary: pattern matching only, clean results are not proof, and hits need human confirmation.

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