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

The annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is established. The description adds valuable behavioral context beyond these: it states the tool 'never authorizes or initiates payment' and returns a 'source-backed deterministic answer' with 'compact maintained-coverage matches.' This extra detail is useful for agent decision-making without contradicting the 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 front-loaded with 'FREE' and 'START HERE,' but it contains unnecessary repetition: 'Default first call for an unfamiliar agent' appears twice, and 'FREE' is also repeated. While the content is useful, the redundancy makes it less concise than it could be. A more streamlined version would earn a higher score.

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?

The description covers the tool's purpose, usage timing, behavioral constraints, and what it returns (source-backed answer, matches, next action). It also addresses payment concerns and directs the agent to evaluate coverage. Since an output schema exists, the lack of explicit return format details is acceptable. The only minor gap is the slight redundancy, but all essential context is present.

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 parameter 'query' with a clear description ('Bitcoin question or research task to answer using maintained California Bitcoin knowledge.') and provides an example. The tool description adds minimal extra parameter semantics—it only restates that it handles 'any Bitcoin question or research task,' which is already implicit in the schema. Since schema coverage is 100%, the baseline of 3 applies.

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 this is a free entry point for any Bitcoin question or research task, returning a source-backed deterministic answer and a smallest safe next action. It distinguishes itself from siblings by explicitly labeling itself as the default first call for unfamiliar agents and the tool to use before any paid option, making its purpose and scope unambiguous.

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 gives explicit when-to-use instructions: 'Default first call for an unfamiliar agent,' 'Use it before any paid tool when coverage has not yet been evaluated,' and 'Do not use it to authorize payment.' It also tells the agent to evaluate coverage before choosing another tool, which is clear guidance on when to use this tool versus alternatives.

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