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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, but the description adds meaningful context: it 'summarizes the local catalog without modifying records,' the shared 60 req/min rate limit across /mcp, and specific error behaviors including HTTP 429 and -32602. No contradiction with annotations.

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 organized into labeled sections (PURPOSE, USAGE, PARAMETERS, BEHAVIOR, RETURNS, ERRORS) with every sentence earning its place. Critical routing information is front-loaded, and there is no redundant filler.

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 zero-parameter list tool, the description covers what the tool returns (totalSnapshots, oldestBlock, newestBlock, availableMetrics, dateBounds), rate limits, and error cases. The output schema exists to define return structure further, so no essential context is missing.

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, the rubric baseline is 4. The description reinforces that no input properties are accepted and clarifies that supplying any will trigger a -32602 error, which adds behavioral meaning beyond the schema's basic 'No input parameters required.'

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 ('Lists complete Bitcoin Stratigraphy catalog coverage and available metric paths') tied to a clear resource. It explicitly distinguishes itself from stratigraphy.get, so an agent can tell them apart.

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?

USAGE explicitly says when to use the tool (discover snapshot, date, block, and metric coverage) and when not to (fetching telemetry records), naming the alternative tool stratigraphy.get. This leaves no ambiguity.

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