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

Annotations already declare readOnly, idempotent, openWorld, non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context: the 6-hour window, 36 sample count, and that the sampled metric differs by chain family (base fee per block on EVM, TPS on Solana). It stops short of noting latency, caching, or resolution, but the added context is substantial.

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?

Three tight sentences with zero filler; the core scope and the 6-hour/36-point specifics lead, and disambiguation against siblings follows. Every clause earns its place.

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?

An output schema exists, so return-value explanation is not required. The description supplies the window, sample density, per-chain metric semantics, and full sibling routing, leaving no gap an agent needs to fill before calling.

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 100% and the single chain parameter carries its own enum and description, so the schema does the heavy lifting. The description's mention of EVM-vs-Solana behavior lightly informs how to read results per chain, but adds no syntax or format guidance beyond the schema. 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 ('Get 6-hour gas fee trend') plus the sampling model (36 data points, EVM base fee per block vs Solana TPS samples). This is enough to distinguish it from gas.tracker, gas.predict, and gas.optimize without opening any 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?

Explicitly frames the tool's scope both positively ('inspect recent fee conditions and trend') and negatively ('not as a current quote or a future forecast'), then routes to each sibling by condition: gas.tracker for now, gas.predict for forecast, gas.optimize for timing. This is textbook when/when-not/alternative guidance.

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