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

Annotations already establish a safe, idempotent, closed-world read, so the description rightly spends its words elsewhere: it discloses the 1-credit cost and that values are 'sourced and dated,' which signals provenance/freshness an agent should not assume elsewhere. It also enumerates what comes back, useful since there is no output schema, though it doesn't state caching or staleness granularity.

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 dense sentences: cost and scope are front-loaded, the field list is packed inline, and the closing call-to-action and provenance note both earn their place. No filler.

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 and low schema coverage, the description carries the return-value burden well by naming each field returned. The remaining gap is the undocumented 'market' parameter and any indication of response shape or per-venue coverage limits.

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 only 33%, and the description clarifies the venue+symbol pairing and implies symbol format varies by venue. However, the 'market' enum parameter (spot/perp/stock/fx) is never mentioned, so the agent gets no guidance on when it is required or how it interacts with venue/symbol.

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 scope — 'Exact trading rules for one symbol on one venue' — then enumerates the concrete fields returned (tick size, lot step, min order size/value, contract value, max leverage, base fee, symbol format, rounding snippet). An agent can tell this apart from venue-wide or prop-firm rule tools without opening the schema.

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?

Gives an explicit trigger: 'Use before writing order-size or price code.' That is clear context for invocation, but there is no exclusion or named alternative (prop_rules, venue_facts) telling the agent where to go for venue-level or firm-level rules instead.

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