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

Annotations already cover read-only, idempotent, non-destructive behavior. The description adds valuable context beyond annotations: the result may include untrusted_model_reason, instructing the agent to treat it as data, not instructions. This is a meaningful behavioral/security disclosure not present in the structured 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 compact and front-loaded with the core purpose. The security warning about untrusted model-generated text is necessary and earns its place. It is dense but not bloated, slightly more complex than needed but still efficient.

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 does a good job enumerating the expected contents: rule-based direction, conditional model direction with levels, graded hit counts with denominators, and untrusted model reasoning. It is sufficiently complete for a read-only informational tool with one optional parameter.

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 100%, and the only parameter, history_limit, is already described as 'Earlier reads to include (compact).' The description does not add additional meaning about the parameter, but the schema carries the full burden, so baseline 3 is appropriate.

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 exactly what the tool returns: the latest scheduled BTC chart read with a rule-based direction, model direction with levels, and graded hit counts. It clearly identifies the resource ('BTC chart read') and is distinct from sibling tools like get_market_snapshot or get_ticker.

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 implies its use case: retrieving the latest scheduled BTC chart read. It adds the important context that this is 'information only; no signal reads it,' but it does not explicitly state when to prefer this over siblings or when not to use it.

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