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

Beyond the readOnlyHint and idempotentHint annotations, the description adds concrete behavioral details: the tool is cached for up to an hour, requires no authentication, returns a not-found error for untraded symbols, and provides sample output content such as source-filing links. This is exactly the kind of context annotations cannot convey.

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 description is detailed but every sentence carries distinct value: output contents, canonical use case, sibling alternatives, error behavior, and access/caching. It is well organized and avoids filler while remaining front-loaded with the most decision-relevant information.

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?

Even without an output schema, the description fully enumerates what the tool returns, specifies error behavior, names alternatives, and covers access and freshness. For a single-parameter read-only tool, nothing needed for correct invocation or interpretation is missing.

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 single parameter is already well-documented with format constraints, case-insensitivity, and an example. The description only repeats 'ticker' and does not add meaningful parameter semantics beyond the schema, so the baseline score 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?

The description clearly states the tool returns aggregated congressional trading data for a single ticker: totals, buy/sell split, dates, top traders, and recent trades. It explicitly frames the use case as "who in Congress trades this stock" and distinguishes itself from list_transactions and cluster_trades, making its purpose unambiguous.

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?

It gives explicit guidance: use this for 'who in Congress trades this stock', use list_transactions for full trade history, and use cluster_trades for coordinated trades. It also notes the not-found error condition and that no key or account is needed, leaving little to inference.

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