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

Annotations already declare readOnlyHint and idempotentHint, covering the non-mutating nature. The description adds useful behavioral context: it explicitly notes that X, Instagram, and TikTok are only manually checked via links, and includes a 'Not legal advice' caveat. This goes beyond what annotations provide 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?

The description is a single, well-structured sentence that front-loads the core action and platform list, then adds manual-check links and the legal disclaimer. Every clause serves a purpose; there is no redundant or filler content.

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 simple one-parameter read-only tool, the description covers the essential scope (which platforms are checked, which are manual, trademark links, and the legal caveat). It lacks explicit return format details, but given no output schema exists, a brief mention of return type could improve completeness. The core information needed to decide on and invoke the tool is present.

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 schema fully describes the only parameter (name) with a pattern, length constraints, and an example. Schema description coverage is 100%, so the description does not need to add parameter details. The description adds no extra parameter semantics beyond the schema, matching the baseline of 3 for high coverage.

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 clearly states a specific verb ('check') and resource ('name free as a handle') across enumerated platforms (GitHub, npm, PyPI, crates.io, YouTube) and trademark databases. It distinctly differentiates from sibling tools focused on domains and DNS by listing social and trademark checks, making the tool's scope unambiguous.

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?

The description implies usage context by listing specific platforms and trademark databases, which clearly separates it from domain-focused siblings. It does not explicitly state when NOT to use it or name alternatives, but the platform list gives sufficient contextual signal for an agent to select this tool for social handle and trademark checks.

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