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

Annotations only declare readOnly and openWorld=false; the description adds substantial behavioral context beyond them: no API key required, the list is LIVE and outranks the sibling tool descriptions, and — critically — that an unregistered jurisdiction returns empty with a 'completed' status that does not mean the company is unregistered. That failure-mode disclosure directly prevents a misread of results.

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 experimental marker and the core purpose, then the precedence rule and fallback semantics. Every sentence carries information, though the trailing 'Examples: company_registries()' block is redundant for a zero-parameter tool.

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?

An output schema exists, so return values need no explanation here. Given a zero-param, read-only list tool, the description supplies everything an agent needs: what it returns, why it matters relative to siblings, and how to interpret empty results.

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?

The tool takes zero parameters, so the baseline is 4. The description correctly shows the no-argument call form rather than implying any input is needed, and the schema is fully documented.

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 ('List available company registries and supported jurisdictions') and distinguishes the tool from its siblings by declaring itself the authoritative source that 'outranks the codes named in those two tools' descriptions.' An agent can identify this without opening the 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?

Explains the context clearly: it is the live list to consult for jurisdiction codes used by company_search_person and company_search_company, and it specifies the fallback ('XX' GLEIF LEI) for unlisted codes. It does not explicitly say 'call this first' as a sequencing instruction, but the precedence rule makes the use case unambiguous.

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