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

The annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds behavioral context by explaining what the tool reveals (coverage per chain), which goes beyond the annotations but does not address other aspects like response format or pagination. Given the annotations already handle safety, this is an adequate contribution.

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, concise sentence that front-loads the core purpose ('What we index per chain for watched addresses') before elaborating on the key aspects. It is efficient with no wasted words, though it could be slightly more explicit about the exact output shape. Overall, it is well-structured and easy to parse.

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?

With no parameters and no output schema, the description is the sole source of information about the tool. It clearly communicates what the tool provides but does not specify the return format or how an agent should interpret the response. For a simple informational tool, this may be sufficient, but more detail on the output structure would improve 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?

The tool has zero parameters, so the baseline for this dimension is 4. The description does not need to explain parameter semantics because there are none. The schema coverage is 100% (vacuously true with no properties), and the description adds no parameter-related information, which is appropriate.

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: to explain what data is indexed per chain for watched addresses, including coverage gaps and the meaning of empty feeds. It names the resource (addresses) and the action (getting coverage info), which distinguishes it from related coverage tools like get_chain_coverage or get_data_coverage. However, it does not explicitly contrast with those siblings, so it doesn't fully exploit sibling differentiation.

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: when you need to understand coverage for watched addresses, especially when an empty feed might be misinterpreted. It does not provide explicit exclusions or alternatives, but the context is sufficient for an agent to infer appropriate usage. The 'what an empty feed actually means' phrase hints at a troubleshooting scenario.

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