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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety bar is low. The description adds genuinely useful context beyond that: what the output means (full vs reduced size), that it is a house-model output cross-checked against a rule in code, and that it is sizing-only. It omits any caveats about staleness or caching, but the added behavioral context is solid.

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 purpose is front-loaded, but the parenthetical model-provenance chain ('trained by the 120B, distilled to the 4B, promoted because it matched the clean room's PROVEN rule on unseen weeks') is internal jargon that consumes a large share of the text without helping an agent invoke the tool. Trimming it would sharpen the definition.

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, idempotent tool with full schema coverage and annotations, the description supplies the key missing piece: what the returned size value signifies (full vs reduced) and that it is sizing-only. No output schema exists, yet the description covers the return semantics adequately; only minor caveats are absent.

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% with a single enum parameter whose default ('all three') is documented in the schema, so the schema does the heavy lifting. The description restates the BTC/ETH/SOL scope but adds no syntax, format, or selection nuance beyond what the schema already provides. 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 a concrete resource (trade size for the crypto session open now) scoped to BTC/ETH/SOL, and explicitly carves out its role as 'a sizing input only, never a direction', which distinguishes it from direction-oriented siblings like forecast. The verb is implicit ('how big to trade') rather than a clean action verb, but an agent can tell what it returns.

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 implies usage by contrasting sizing vs direction, and explains the two output regimes (full size when vol is high, reduced when quiet), which helps interpret results. However, it never states when to call this tool versus alternatives, nor any prerequisites or timing constraints.

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