scan_pii

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

With no annotations, the description carries the burden and does reasonably well: it discloses the return shape ('full ScanResult with per-match details') and the key behavioral caveat that in-line redaction produces placeholders that are not reversible. It omits auth, rate limits, and performance characteristics for large inputs, leaving some gaps.

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 short sentences: what it scans, what it returns, and where to go instead. The capability statement is front-loaded and every sentence earns its place.

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 two-parameter, non-mutating scan tool with no output schema, the description supplies return-shape information that would otherwise be missing and covers the reversibility trade-off. Only secondary operational details are absent, which are not essential to calling it 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 coverage is 100%, and the schema's own description of 'redact' already explains the placeholder behavior and points to redact_pii. The description therefore adds no parameter meaning beyond the structured field, so 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 ('Scan text for PII') and enumerates the detected entity classes so the agent knows exactly what comes back. It also names the sibling it is not (redact_pii), making it distinguishable without opening either 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?

Explicitly routes the agent to redact_pii when a reversible vault-backed redaction is wanted, establishing the main selection criterion. It stops short of stating exclusions or the alternative paths among the other siblings (scan_secrets, detect_obfuscation), so it is clear but not exhaustive.

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