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

Annotations already carry the safety profile (readOnly, idempotent, closed-world), so the bar is lower. The description adds real operational context beyond that: the 1500-character query cap, that ratios must be EXACT names, that an invalid query errors with the offending token named, and that cross-field comparison is permitted. It does not disclose pagination/result-format behavior, which is a minor remaining gap.

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?

Purpose and the sibling alternative are front-loaded, then a clearly labelled QUERY SYNTAX block, ratio list, example, and a final note. Despite being dense, every block is headed and each earns its place; no filler sentences.

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 a complex filter tool with 6 params and no output schema, the description covers invocation thoroughly (syntax, limits, errors, ratio catalog, alternatives). The one omission is any hint of what the response contains (result shape/pagination semantics), which the absent output schema leaves to the description.

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 baseline would be 3, but the description enriches the critical `query` parameter far past the schema's one-line example: it documents the operator set, AND/OR connectors, per-line grouping, cross-field comparisons, exact-name matching, a starter list of common ratio names, and a worked example. That is substantial added meaning for the parameter that drives the call.

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+"scope ("Screen Indian stocks by fundamental criteria using 325 financial ratios") and explicitly names the sibling it is not (screen_stocks_technical). An agent can distinguish it from the technical screener and from get_screener_ratios without opening any 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?

Names the alternative explicitly ("For technical screens ... use screen_stocks_technical instead") and routes the agent to get_screener_ratios for unknown ratio names and to read_me for stock disambiguation. When-to-use, when-not, and the fallback tools are all stated.

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