query_metric

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

No annotations exist, so the description carries the full behavioral burden. It usefully discloses the governance/refusal model and that errors are self-correcting, which is real value beyond structured fields. It does not state side-effect profile, permission prerequisites, or rate/cost limits, leaving meaningful gaps for a tool with zero annotation coverage.

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?

Four short sentences, front-loaded with the core action, then the exclusivity constraint, then error behavior. Nothing is bloated. The 'only way to aggregate' and 'free SQL does not exist' lines are near-duplicates, costing a little tightness.

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?

The output schema is present, so return values need no explanation, and the governance framing is well covered. However, with five undocumented parameters at 0% coverage and no annotations, an agent still lacks guidance on how to build a valid metric/filters/dimensions call. Adequate but with a clear structural gap.

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 0% across five parameters, and the description names none of them (metric, filters, dimensions, limit, horizon_days). The pointer to semantic://layer is a partial offset, since metric and dimension names likely live there, but no parameter meaning, format, or default behavior is conveyed in the description itself.

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: 'Run a governed metric from the semantic layer.' The exclusivity claim ('the only way to aggregate') further pins down its role relative to the sibling search/get tools, though it never names those siblings directly. An agent knows what this does without opening the 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 routing guidance: this is the only aggregation path, free SQL does not exist, and refused queries surface corrective GovernanceError messages. It tells the agent when to reach for this tool and what to do on failure. It stops short of saying which sibling to use for non-aggregate retrieval, so a 4 rather than a 5.

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