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

Since there are no annotations, the description must carry the full burden. It discloses that the tool is read-only (returns data) and details what is NOT included (e.g., no names/addresses), which is useful. It also mentions a unique behavior: every response includes an 'unlock' block with pricing info for a paid endpoint, which is helpful. It doesn't specify rate limits or error cases, but for a no-parameter read tool, this is sufficient.

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 moderately concise with two paragraphs. The first paragraph states the primary function and output format, which is good front-loading. The second adds the paid counterpart and unlock block, which is useful but slightly verbose. Each sentence contributes value, though the second paragraph could be tightened without losing key info. It is structured but not overly long.

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 has no parameters, no output schema, and no annotations, the description is complete enough for an agent to call it correctly. It explains what to expect in the response (counts, per-chain breakdown) and the paid upgrade. There is no missing information that would prevent correct usage.

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?

With zero parameters and 100% schema coverage, the schema itself doesn't provide any parameter details. The description compensates by explaining the type of data returned (counts, breakdowns, per-chain) and the additional unlock block. This is valid because the tool takes no arguments, so the description effectively clarifies what the tool provides given no inputs.

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: 'Live coverage of the ERC-8004 agent economy' with specific output details. It distinguishes itself by emphasizing it returns counts only, not actual names or addresses, which differentiates it from siblings like get_agent_summary. The verb 'get' and the resource 'coverage stats' are explicit and precise.

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 provides clear guidance on when to use this tool: to 'size the market' and see where capability density is growing. It also mentions a paid counterpart for more detailed data for those needing capability-level specifics. However, it does not explicitly state when NOT to use this tool or mention alternatives like get_agent_summary, though the definition implies the free/paid distinction.

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