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

Beyond the readOnlyHint/openWorldHint annotations, it discloses that free access is delayed with the newest points omitted and that the response carries pointsRemoved and remedy_url, plus an explicit cost of 1 request unit. That is exactly the operational context (data truncation, quota cost, remediation path) an agent needs before invoking.

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 domain label is front-loaded, followed by the family enumeration and then parameter rules in priority order. It is dense and somewhat run-on across many short clauses, but essentially every sentence carries a distinct rule 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?

For an 8-parameter, no-output-schema tool, the description covers the family taxonomy, series/catalog behavior, date semantics, cot-only filters, and free-tier return caveats. The main omission is that it never describes the shape of a returned series or catalog entry, though pointsRemoved/remedy_url are called out.

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%, so the schema documents each field, but the description adds conditional meaning the schema lacks: which families accept series, that from/to apply to a single series, that cot's active/set/contract/report filters only apply when series is omitted, and the index-symbol format (GSPC.INDX). It exceeds the baseline-3 expectation for full-coverage schemas.

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 names a specific resource domain ('Market sentiment') and enumerates all seven sub-families (breadth, breadth_volume, naaim, fear_index, smart_money, cot, sce), so an agent knows exactly what data it returns. It does not state an explicit verb (retrieve/list) or name a sibling tool, but the resource is distinct from anything in the sibling list (prices, news, macro, etc.).

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 concrete routing rules: for breadth/breadth_volume/cot/sce omit series to list the catalog and pass series to read one; naaim, fear_index, and smart_money are single series so omit series entirely. It also scopes cot filters to the catalog-listing case. It stops short of naming alternative tools for when sentiment is the wrong choice.

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