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

Annotations already declare readOnly, idempotent, and closed-world, so safety is covered. The description adds meaningful operational context: stale/future and uncovered/unconverted venues are withheld, fees are excluded, and no trade clearance is provided. It doesn't describe return format or failure behavior, so not a 5.

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?

Two tight sentences (with semicolons) front-load the core comparison and then the data caveats. No filler; every clause contributes.

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 purpose and key data limitations, which is useful for a read-only tool whose annotations cover safety. However, with no output schema and zero schema description coverage, it leaves parameter meaning and result format insufficiently explained for an agent to call with full confidence.

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 must compensate. It only indirectly hints at sizes_usd ('four BTC sell sizes') and max_age_seconds ('stale/future'), but does not explain units, array expectations, age cutoff, or defaults, leaving parameter meaning largely in the schema's types alone.

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?

States a specific verb (Compare) and resource (BTC sell sizes) and scopes it to four sizes by rung/bracket. It does not explicitly differentiate from sibling tools like exit_cost or trade_safety_exit_context, so it falls short of a 5.

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?

No when-to-use, prerequisites, or alternative tools are named. The constraints about withheld venues and fees describe behavior, not when to choose this tool over siblings such as exit_cost.

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