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

Adds substantial behavioral context beyond annotations: cost model ('$0.01/call via x402 USDC or a card key, first 25 free; failed calls free'), repeat-call charging ('each call is charged, so repeats are not free'), output masking ('hits are shown masked'), and input limit ('up to 20,000 characters'). These details complement the readOnlyHint and openWorldHint annotations without contradicting them.

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?

Front-loads the core purpose and detection capabilities, then adds practical details. It is dense but mostly earns its space; the pricing sentence is slightly tangential to the scanning purpose but relevant for cost-aware agents.

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?

Given the tool's complexity, two parameters, no output schema, and annotation coverage, the description is complete. It explains output shape ('each with its position, plus the text with every hit replaced by a label such as [EMAIL]'), input limits, detection scope, masking, and cost/auth requirements.

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?

With 100% schema description coverage, the schema already defines both parameters. The description adds an illustrative example ('text=Contact Anna at anna.berg@example.com...') and restates the detectable types, giving useful usage context even though it largely mirrors the schema's 'types' description.

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 ('Find personal data... and get it back redacted') and enumerates the detected entity types (emails, phones, Luhn-checked cards, IBANs, SSNs, IPs, crypto addresses), clearly distinguishing this text-scanning/redaction tool from sibling tools like text_prompt_injection.

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?

Provides clear when-to-use guidance: 'Use before logging, storing or sending text to a model.' Also states a key limitation ('names and street addresses are not detected'). No explicit alternatives or when-not-to-use conditions are named, keeping this just below a 5.

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