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

Annotations already declare readOnlyHint=true, so the baseline bar is lower. The description adds meaningful context by disclosing a payment requirement ("PAID $0.50 USD via Stripe MPP") and by listing the evidence package components. There is no contradiction with the read-only annotation because "Build" here implies assembling a response, not modifying external state.

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 short and mostly to the point, but the payment notice is placed before the actual purpose, which hurts front-loading. The core sentence is efficient, but the overall structure prioritizes a billing detail over the tool's function.

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 only one parameter and a read-only annotation, the description does not need to be long. However, it leaves the query semantics unexplained and offers no routing context among seven related sibling tools. The output components it lists are helpful, but the package's exact scope and response format remain underspecified.

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?

Schema description coverage is 0%, so the description needed to clarify what the "query" parameter should contain. It does not; the parameter meaning is only weakly implied by the tool name and package-building phrase. This is a clear gap.

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 clear action, "Build a structured evidence package," and specifies the output contents: claims, source classes, provenance, history, and related concepts. This distinguishes the tool's purpose from siblings at a general level, though it does not explicitly name a differentiating sibling.

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 no guidance on when to use this tool instead of alternatives like answer_bitcoin_question, verify_bitcoin_claim, or get_bitcoin_topic. It also does not state what kind of query is appropriate or any exclusions.

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