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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered and the description correctly avoids repeating it. The description adds genuine value by stating what each story returns (publication and ingestion timestamps plus source links), which matters because there is no output schema. It does not disclose ordering, pagination, or rate-limit behavior, and the semantics of the feed values remain unexplained.

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?

Four tight sentences, front-loaded with the verb and resource, then filtering axes, then the topic vocabulary, then return content. No filler; the only trimming opportunity would be folding the topic-code list into a more compact form.

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 closing sentence about timestamps and source links usefully covers return content, and the topic codes fill the biggest parameter hole. However, for a discovery tool the meaning of 'top' versus 'breaking' versus 'latest' is an operational decision the agent cannot make from the schema enum alone, and it is left unexplained.

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 0% for four of the five parameters, so the description carries most of the burden — and it does for the hardest one, spelling out the topic NI codes (mna, cb, energy, metals, reg, crypto, earn, ipo) or a category id, which is not in the schema at all. The tickers parameter is illustrated in the schema itself. The gap is the feed enum: 'latest', 'top', and 'breaking' are never explained, and limit is unmentioned.

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 ('Search or list market-news stories') and names the filter axes, so the agent knows this is a news retrieval tool, not a quote or filings tool. It does not explicitly differentiate itself from the nearest siblings such as social.search_posts or sec.filings, which is why it falls short of a 5.

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?

Usage is only implied through the phrase 'Filter by feed, text, tickers, or topics' — the agent can infer that this is the tool for news lookups. There is no statement of when to prefer it over social.search_posts or sec.filings, no prerequisites, and no exclusions.

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