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

Annotations already cover the read-only and open-world profile, and the description adds genuinely new behavior: a $0.002 USDC charge per successful call via x402 on Base/Solana/Arc, with failed calls free. That billing semantics is material for an agent deciding whether to retry or batch. It omits rate limits and data freshness/latency, which would complete the picture.

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?

The core capability and section list are front-loaded in the first sentence, with constraints, exclusions and pricing following in priority order. It is dense but every sentence carries distinct information; the parenthetical about no free source for entity tags is slightly more justification than an agent needs.

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 values need no explanation; the schema fully documents all three optional parameters. The description covers what a caller still needs and cannot infer: source restriction to BBC, absent fields, and the paid-call model including which failures are free. Nothing material is missing for correct invocation.

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%, so the schema already documents q (keyword, length bounds, matching in title or summary), limit (1-30, default 10) and section (enumerated values, default world). The description only restates that a claim is 'optionally filtered by a keyword' and that one section feed is used, adding no syntax or edge-case detail 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+resource ('Latest BBC News headlines from one section feed'), enumerates the exact section values, and specifies what each item contains (summary, link, publication time). An agent can distinguish this from generic siblings like agent_intel_web_search_turbo 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?

The 'BBC only: no other publishers, no entity tags and no trust rating' sentence functions as an explicit exclusion list, telling the agent when this tool is the wrong choice (e.g., when entity tagging or credibility scoring is needed). It stops short of naming the specific alternative sibling to use in those cases.

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