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

No annotations are present, so the description carries the behavioral burden. It discloses that the tool is paid, compact/low-cost, returns summary regime data rather than the full surface, and is not validated directional alpha. It could go further on failure modes or rate limits, but for a read-only regime check the key cost and scope behaviors are covered.

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 sentences front-load the core purpose, then cover usage, return contents, caveat, and catalog pointer with zero filler. Every sentence earns its place.

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 output schema, the description provides the needed return categories: regime state, normalized surface statistics, venue coverage, and freshness. It also covers cost/availability and names the exact venues. The output shape is somewhat unspecified, but the branch-on-state use case is clear enough for an agent to invoke 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 schema already documents the single optional payment_signature parameter at 100% coverage, including its x402 header purpose and min length, so the description adds no new parameter-level detail. The baseline of 3 applies because the schema does the heavy lifting.

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 uses a specific verb and resource: a 'compact BTC perpetual-funding regime read' across four named venues. It also distinguishes itself from the sibling 'full funding surface' by calling itself a low-cost branch-on-state check, so an agent can tell it apart immediately.

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 says 'Use as a low-cost branch-on-state check before requesting the full funding surface,' which names the alternative and the condition that selects it. It also gives a when-not by stating it is 'not validated directional alpha' and points to rcq://catalog for availability and price.

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