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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that it honors the same technology/category/domain/reachability/rendering filters as search, which is useful context. It does not disclose pagination behavior or result shape, but with annotations carrying the read-only profile a 3 is appropriate.

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?

Two sentences, zero waste. The core behavior is front-loaded, and the sibling routing follows immediately. Every clause earns its place.

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 no explanation, and a read-only facet tool with 100% schema coverage is well served by this description. It covers purpose, filter inheritance, and routing. A marginal gap remains around whether facets respect pagination or aggregate the full filtered set, but overall it is complete for this tool class.

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 all 22 parameters are already documented in the schema. The description enumerates filter dimensions (technology, category, domain, reachability, rendering) but adds no syntax, format, or default detail beyond the schema. Baseline 3 when the schema does the heavy lifting.

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: 'Return facet-distribution data for the stored website tech-stack dataset.' This clearly distinguishes it from search (matching sites) and item (one record) within the same family, so an agent can tell the three apart without opening schemas.

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?

Explicitly routes the agent: 'Use datasets_techstack_search for matching sites or datasets_techstack_item for one record.' This gives clear alternatives for different intents. It stops short of an explicit 'use this when you need distributions' statement or exclusions, but the routing is unambiguous.

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