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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior, yet the description adds substantially: explicit return fields, the null base_fee case on non-EIP-1559 chains, latency (~0.2-1s), pricing, quota limits, and a prompt-injection warning about untrusted on-chain/page text. This is rich behavioral context beyond the structured fields.

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 action and scope, then methodically layers inputs, outputs, cost, quota, and a safety note. Every sentence carries distinct operational value with 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, the description compensates by enumerating the returned fields and the null base_fee edge case. Combined with annotations covering safety semantics, an agent has everything needed to call correctly.

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 enum already restricts chain to ethereum|base; the description restates those values without adding format or edge-case meaning. Baseline 3 applies when the schema does the heavy lifting.

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+resource ('read the current gas price') and scopes it to Ethereum or Base, which cleanly separates it from siblings like get_block and get_transaction. An agent can identify the tool's function 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?

Implicitly conveys the use case (fetching current gas price) and adds operational context — latency, per-call cost, and the shared free-tier pool across chain reads, sanctions screen, and URL check. It stops short of naming an alternative (e.g., get_block already returns base fee), so it's clear but not fully routed.

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