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

Annotations cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds critical non-obvious behavior: this is deprecated, financial/credit sources are unavailable, and returned fields are null. That directly prevents an agent from trusting garbage output.

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?

A single sentence, and the deprecation notice is front-loaded before any other content. Every clause earns its place: replacement tool, usage condition, and the null-field warning.

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 deprecated tool with no output schema and all-optional params, the description supplies exactly what's needed: don't use it, here's the replacement, and the output is empty anyway. Nothing an agent requires to call or avoid it is missing.

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% with three optional, self-documented parameters, so the baseline is 3. The description adds no parameter-level meaning (e.g., which identifier wins if both siren and company_name are given), leaving the schema to carry it.

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 names the operation (company analysis), its deprecated status, and the exact sibling to use instead (factrail_verify). An agent can distinguish it from factrail_verify and verify_french_company purely from the text, with no schema inspection needed.

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 and when-not-to-use: only call it when a legacy integration still invokes the experimental path, and use factrail_verify otherwise. Both the condition and the alternative are stated without inference.

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