find_favicons

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly explains the methods used (checks /favicon.ico, parses HTML link tags, inspects manifest.json) and the return value (all found favicons with sizes and types). This goes beyond a simple mutation hint and gives the agent a realistic picture of the tool's operations, though it omits details like error handling or redirect behavior.

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 extremely concise at two sentences. The first sentence states the core action, and the second adds the methods and output in a structured way. There is zero filler or redundancy, making it easy for an agent to parse quickly.

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?

Given the tool's simplicity (one parameter, no output schema, no annotations), the description is quite complete: it covers what the tool does, how it does it, and what the response includes. The only missing piece is a concrete example of the returned data structure, but the mention of 'sizes and types' gives a reasonable picture. For a tool of this complexity, this is above-average completeness.

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 coverage is 100% because the only parameter 'url' has a descriptive text ('Website URL to find favicons for (e.g. https://example.com)'). The description adds no new parameter-specific meaning beyond what the schema already provides, so the baseline 3 applies.

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 ('Find') and resource ('all favicons for a website'), and clearly distinguishes itself from sibling tools like extract_og_image and image_metadata by focusing solely on favicon discovery. It also enumerates the exact sources checked (favicon.ico, HTML link tags, manifest.json), leaving no ambiguity about its purpose.

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 when to use the tool (whenever favicons are needed for a website) but does not explicitly state alternatives or exclusions. While the context is clear, the agent is not told to prefer this over siblings or what conditions make it unsuitable, so usage guidance is only implicit.

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