topai_disposable_email_shield

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

Adds return semantics the annotations do not carry (a 0.0–1.0 fraud risk score) and names the detection techniques. The closing 'Stateless, read-only, idempotent verification' largely restates the annotations, and 'DNS MX heuristics' sits in mild tension with openWorldHint=false since MX lookups are network-dependent — but this is a nuance, not a hard contradiction.

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-loaded with the core purpose, then usage, then an exclusion, then a behavioral tagline — four efficient sentences. The final sentence duplicates annotation content and could be dropped without loss.

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?

No output schema exists, and the description fills that gap by stating the return value and its range. Combined with explicit usage/exclusion guidance and method disclosure, an agent has everything needed to select and invoke 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?

Only one parameter with 100% schema description coverage, so the schema already documents the email string, its format, and an example. The description adds no parameter-level detail beyond the schema, which is the expected baseline when coverage is complete.

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?

Specific verb+resource: 'Detects disposable, burner, or temporary email addresses', plus the detection methods (RFC 5322 parsing, throwaway domain blocklists, DNS MX heuristics) and the return value (fraud risk score 0.0–1.0). This clearly distinguishes it from siblings like topai_prompt_shield or topai_healthcare_validator.

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?

Explicit when-to-use scenarios (user signup, B2B lead cleaning, KYC fraud prevention) and an explicit when-NOT-to-use case that names the alternative tool: 'Do not use for enriching corporate firmographics ... use topai_company_enrichment instead.' Full routing guidance.

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