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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: the size and composition of the result set (16 factors, 7 significant, 9 moderate; 7 signals) and the nature of the values returned. It omits pagination, caching or freshness caveats, but there is an output schema for structure.

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?

Three sentences, front-loaded with the resource and its scope, then content, then usage triggers — every sentence carries information. The middle proprietary-signal list is long but is the main differentiator, so it largely 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?

With an output schema present, the description need not explain return structure, and it still summarizes the returned metrics. Domain (NZX), scope, filters and use cases are all covered; a reader has everything needed to invoke it correctly.

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%, so both filters (category, significance) are already documented in the schema with their allowed values. The description adds no parameter-level guidance such as default behaviour when category is omitted or how comma-separated values interact, so 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?

States a specific verb and resource ("Get NZX factor validation results") and immediately scopes it with concrete content: 16 backtested factors with IC, t-statistics, hit rates, direction and significance, plus 7 proprietary signal backtests. The enumeration of validation outputs (statistical significance, coefficients) is enough to separate it from factor-grade/model siblings without the agent 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?

Ends with an explicit trigger list: "Use when asked about which factors work on the NZX, alpha signals, backtested strategies, or factor investing." That is clear context for selection, but it names no alternative tools (e.g. get_factor_grades, get_alpha_factors) and states no when-not-to-use condition.

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