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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description's added behavioral context is thin: it clarifies the tool operates over a universe rather than a single entity, but says nothing about result pagination behavior, filter combination semantics (AND vs OR), or cost/latency beyond what the schema already implies.

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?

Front-loaded with the core capability, then capabilities, then routing caveats. The long preset enumeration and duplicated filter example are somewhat redundant given the schema, but every sentence is functional and the routing block earns its space.

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 not be described. For a 7-parameter, zero-required screening tool, the definition supplies the universe scope, capability surface, routing exclusions and invocation examples needed to call it correctly; nothing material 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 description coverage is 100% and the schema already lists the preset values, filter syntax, sort examples and limit bounds. The description restates the same preset list and the same filter example ('pe_ratio<15,rsi_14<30'), so it adds little semantic value beyond the structured fields; 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?

Specific verb+resource+scope: 'Screen NZX stocks across 87+ metrics' with an enumerated domain (financials, valuation, technical, governance, insider activity). The ROUTING paragraph explicitly separates it from dataset siblings like get_executive_compensation and get_remuneration, so an agent can discriminate without opening a 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?

Explicit when-to-use is given with concrete query examples ('show me oversold stocks', 'value stocks with high dividends'), plus a when-NOT-to-use rule ('use this only to FILTER a universe... not the source for one company's figures') and named alternatives for the excluded cases.

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