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

No annotations are provided, so the description must carry the full behavioral burden. It explains what inputs are accepted, but does not disclose return shape, no-match behavior, failure modes, or any side effects. The trailing 'Understanding plan.' adds no behavioral information.

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 main sentence is compact, specific, and front-loaded with the most important scoping information. However, the trailing 'Understanding plan.' is an unexplained, non-functional fragment that should be removed.

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 two-parameter lookup tool, the core input semantics are covered and the intended outcome ('provider it belongs to') is clear. With no output schema or annotations, though, the description does not specify what the agent should expect as a result or how unresolved identifiers are handled.

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%, and the schema already documents both 'identifier' and 'context' well. The description mostly restates the identifier examples from the schema and adds no new parameter-level guidance.

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 uses a specific verb ('Resolve'), names the target resource ('the apis.io provider'), and gives concrete examples (URL, domain, GitHub org). The 'not a slug' clause helps distinguish it from slug-based lookups, making the tool's role clear.

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?

It explicitly states the condition for use: 'Use this when you have a URL, not a slug,' which is clear and actionable. It does not name an alternative tool for slug-based lookups, so it stops short of full alternative routing.

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