Verify the fetchproxy bridge end-to-end

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

Annotations already mark the tool as read-only, open-world, and idempotent. The description adds useful behavioral detail by specifying the round-trip mechanism, the exact diagnostic fields returned, and the three failure categories ('bridge never came up', 'extension not connected', 'real www.zillow.com-side problem'). 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?

The description is compact yet information-dense: the first sentence explains mechanisms and outputs, the second covers when to use it and safety. There is no filler or repetition of schema information, and the diagnostic output list is clearly structured.

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 there is no output schema, the description adequately enumerates the return diagnostics including role, port, version, extension link state, elapsed time, and the plain-English hint. It also covers the trigger scenario and safety profile, making it complete for an agent to invoke and interpret correctly.

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 tool has zero parameters and the schema coverage is 100%, so the description carries no parameter burden. The baseline of 4 applies for zero-parameter tools, and the description appropriately focuses on behavior and outputs rather than parameter details.

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 states a specific verb and resource: it 'Round-trips a small public www.zillow.com URL (/robots.txt) through the fetchproxy bridge' and returns diagnostics. This clearly differentiates it from the data-retrieval sibling tools by framing it as a diagnostic healthcheck rather than a data lookup.

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 explicitly says 'Call this when a real tool fails and you want to know which hop broke,' giving a clear trigger condition. It does not explicitly list when-not-to-use or name alternative diagnostic tools, but siblings are all data-oriented, so the use case is evident.

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