gas_tracker

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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds genuinely new context: free pricing, no API key, nothing signed or spent, and the failure mode (error on unknown symbol or unreachable upstream). It stops short of stating rate limits or caching freshness, which for a 'current' price feed would be the one remaining useful disclosure.

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 purpose, then labeled sections (Use when / Not for / Returns / Example / Price) that make it skimmable. Slightly long for a zero-parameter read tool, and the inline example response duplicates the field list above it, but no sentence is wasted.

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?

There is no output schema, so the description carries the return burden and does it well: named fields (slow_gwei, standard_gwei, fast_gwei, base_fee_gwei, confirmation times) plus a concrete example payload. Combined with the failure-mode and cost notes, an agent has everything needed to call and interpret it.

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?

Zero parameters, so the baseline is 4; there is nothing for the description to disambiguate. The description correctly avoids inventing parameter semantics for a no-arg tool.

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 current Ethereum gas prices') plus the three tiers (slow, standard, fast), and explicitly scopes it to Ethereum mainnet only. An agent can distinguish it from the 19 siblings, including the one that overlaps (market_snapshot).

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?

Uses an explicit 'Use when' / 'Not for' structure and names the alternative route (market_snapshot already includes standard gwei) with the condition that selects it. Nothing is left to inference about when to pick this tool.

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