robots_txt

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

With no annotations, the description carries the full burden. It discloses that it fetches and parses, and enumerates the return contents (user-agent rules, allowed/disallowed paths, sitemap directives, crawl-delay, issues). While it doesn't cover error/edge cases, it provides sufficient behavioral detail for a simple read-only tool.

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 with no waste. The first sentence communicates function and output, the second gives the usage purpose. Every word 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?

The tool is simple with one parameter and no output schema. The description lists the return types and usage, making it complete for the tool's complexity. There's no missing critical information.

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% — the single 'url' parameter is fully described in the schema ('Domain or URL... Will check /robots.txt at the root'). The description adds no additional parameter-level detail, so it's at the baseline.

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 'Fetch and parse a site's robots.txt' with a specific verb and resource. It also lists what it returns, distinguishing it from sibling SEO tools like sitemap_check.

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?

Explicitly says 'Use this to check what search engines can/cannot crawl,' providing a clear use case. It doesn't mention exclusions or alternatives, but given the sibling tools, the purpose is differentiated enough that usage context is apparent.

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