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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds genuinely new behavioral facts beyond them: the output is deterministic and no LLM/credits are consumed ('Free'), which matters for an agent deciding between this and a generative sibling. It omits response size, latency/fan-out cost, and whether venue coverage varies by symbol.

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?

Front-loaded with the core identity, then a dense but purposeful enumeration of returned sections; every clause maps to actual output content. The single-sentence catalogue is information-dense to the point of being a wall of comma-separated items, which slightly hurts scanability, but no sentence is wasteful.

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 only one fully-documented parameter and no output schema, the description carries the entire burden of explaining what comes back, and it does so item by item, including the modeled-risk and flow fields an agent could not otherwise anticipate. Combined with the 'Free, no LLM' framing, an agent has enough to decide to call it and to interpret the result.

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 schema already documents the BASEUSDT format with examples and the 1000PEPE/kPEPE folding rule. The description only restates that the input is a 'perp symbol', adding no format, normalization, or default-handling detail beyond the schema, so the baseline 3 applies.

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 and resource ('Deterministic market brief for a perp symbol') and then enumerates the exact contents: 24h liquidations, funding + extremes per venue, OI with 1h/4h/24h deltas, net flows, modeled liquidation zones, top-trader positioning. That enumeration makes clear it is the composite/aggregate tool rather than any of the single-metric siblings (get_open_interest, get_funding_rates, get_liquidations), and 'no LLM involved' separates it from the ask/explain_market family.

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 a clear usage context: it is the raw, deterministic input intended for the agent's own reasoning, which implicitly tells the agent to pick this over the LLM-backed ask/explain_market when it wants to do the analysis itself. It does not name explicit alternatives or state when NOT to use it (e.g., when only one metric is needed, prefer the focused sibling), so it stops short of full routing guidance.

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