httpcat

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

With no annotations provided, the description carries the full burden. It discloses the output behavior ('Returns a direct URL to a cat photo'), which is helpful, but doesn't mention error handling (e.g., for invalid codes), rate limits, or authentication needs. It adds some value but lacks comprehensive behavioral context for a tool with no annotations.

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 two sentences with zero waste: the first states the purpose, and the second clarifies the return value. It's front-loaded and appropriately sized for a simple tool, making it easy to scan and understand 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 low complexity (one parameter, no output schema, no annotations), the description is mostly complete. It covers purpose and output, but lacks error handling details or explicit sibling differentiation. For a simple lookup tool, this is sufficient but could be slightly enhanced for full 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 description coverage is 100%, so the schema already documents the 'status_code' parameter with examples. The description adds no additional meaning beyond what's in the schema (e.g., it doesn't specify valid code ranges or format details). Baseline 3 is appropriate as the schema does the heavy lifting.

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 the specific action ('Get the http.cat image URL'), identifies the resource ('for a given HTTP status code'), and distinguishes from the sibling tool 'list_codes' by focusing on retrieving a single image URL rather than listing codes. It provides a complete picture of what the tool does.

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 by mentioning 'a given HTTP status code,' suggesting it's for when you have a specific code to look up. However, it doesn't explicitly state when to use this tool versus the sibling 'list_codes' (e.g., for browsing codes vs. getting an image for a known code) or provide any exclusions or prerequisites, leaving some guidance gaps.

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

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

No annotations are provided, so the description carries the full burden. It discloses that the tool lists codes with descriptions and image URLs, which is useful behavioral context. However, it does not mention potential limitations like rate limits, data freshness, or response format details, leaving some behavioral aspects unspecified.

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, efficient sentence that front-loads the key information ('List common HTTP status codes') and adds necessary details ('with their descriptions and corresponding http.cat image URLs') without any wasted words. Every part of the 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?

Given the tool's low complexity (0 parameters, no annotations, no output schema), the description is complete enough for its purpose. It clearly states what the tool does and what information it provides. However, without an output schema, it could benefit from more detail on the return format, but this is a minor gap for such a simple tool.

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 input schema has 0 parameters with 100% coverage, so no parameter information is needed. The description does not add parameter semantics, but this is acceptable as there are no parameters. A baseline of 4 is appropriate for tools with zero parameters.

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 the tool's purpose with specific verbs ('List') and resources ('common HTTP status codes'), and distinguishes it from the sibling tool 'get_status_cat' by specifying it lists multiple codes with descriptions and image URLs, whereas the sibling likely retrieves a single code.

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 for retrieving a list of HTTP status codes with descriptions and image URLs, but does not explicitly state when to use this tool versus the sibling 'get_status_cat' or provide exclusions. The context is clear but lacks explicit alternatives or when-not guidance.

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