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

No annotations provided, so description must cover behavior. It mentions pricing ($0.002/call, 50 free/day) which is valuable, but does not disclose network behavior, authentication needs, or response limits. Some behavioral context is provided but not comprehensive.

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?

Two sentences: first clearly states purpose, second adds pricing info. No fluff, front-loaded. Every sentence earns its place.

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, so description should explain return format. It says 'Rich embed (oEmbed) data' but lacks detail on structure (e.g., JSON fields). For a simple one-param tool, this is adequate but not fully complete.

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?

Parameter 'url' is 100% covered by schema description, so baseline is 3. The tool description adds context about supported media URLs but also introduces ambiguity by allowing 'hostname' in schema, which may not work for oEmbed. Adds some value but could be clearer.

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?

Description clearly states it provides 'Rich embed (oEmbed) data for a media URL' with specific examples (YouTube, Vimeo, X, Spotify). This distinguishes it from siblings like unfurl_url which may provide other metadata.

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?

No explicit guidance on when to use this tool vs alternatives. The listed platforms hint at suitability, but no when-not conditions or comparisons to sibling tools are given.

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