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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds genuinely useful model caveats beyond that: fees excluded, not executable, and interpolated from bid-depth bands, telling the agent these are estimates rather than tradable quotes.

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 compact clauses, front-loaded with the core action and the key limitations, followed by the sibling reference. No filler or repetition of the title.

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?

For a one-parameter, read-only estimator with no output schema, the description covers what is computed, how it is derived, and its limits. It does not characterize the returned structure (e.g., per-venue rows), which the absence of an output schema would have made worthwhile.

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 coverage is 100% and the sole parameter's description already explains the $1,000–$1,000,000 published rungs and nearest-rung selection. The description's 'interpolated bid-depth bands' adds some framing but sits in slight tension with the schema's 'nearest rung is used', so this stays at the baseline 3.

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 resource and action ('BTC nearest-rung sell estimates, interpolated bid-depth bands') and names the sibling it is not (crypto_exit_check), so the agent can route correctly. The domain shorthand ('rung', 'bid-depth bands') is jargon-heavy, which slightly blunts immediate comprehension, keeping it below 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?

It contrasts itself against crypto_exit_check by describing what that sibling does ('compares sizes/freshness'), which implies this tool is for a single-size estimate. It is clear context but stops short of an explicit 'use X when / use Y when' rule.

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