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

With annotations already marking readOnlyHint and idempotentHint, the description adds valuable context: it notes the tool does not execute JavaScript or bypass access controls, and explains cache behavior with the fresh flag. This goes beyond the structured annotations without contradicting them.

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?

Three short sentences immediately lead with the purpose and then cover constraints and parameter usage. There is no redundant fluff; every clause adds information.

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 read tool with rich annotations and an output schema, the description covers the core behavior, safety guarantees, and parameter usage. It doesn't need to explain return values because an output schema exists.

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 already documents all parameters with high coverage, so the baseline is 3. The description reinforces the schema by stating 'Pass url as an absolute public HTTP(S) URL' and adds practical advice on when to set fresh=true versus false, slightly elevating its contribution.

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 opens with 'Report the robots.txt policy decision applied to the requested URL,' specifying a clear verb and resource (robots.txt policy) and distinguishing it from sibling site tools like web.site.sitemaps. This makes the tool's purpose unambiguous.

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 limits usage to public HTTP(S) resources and notes it does not execute JavaScript or bypass access controls, which helps an agent choose it only for appropriate URLs. It provides parameter-level guidance with the fresh flag, though it doesn't name specific alternative tools.

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