aggregate_across_instances

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

Annotations declare readOnlyHint, destructiveHint, idempotentHint, and openWorldHint. Description adds 'fanned out across instances' and 'combined grand totals', providing context beyond annotations but lacking details on how aggregation works.

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?

Single sentence, front-loaded with key information ('Read-only aggregate'). No waste.

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 5 parameters, 0% schema coverage, and an output schema, the description is insufficient. It does not explain parameter usage, return format, or prerequisites for cross-instance aggregation.

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%, and the description does not explain any parameter. Parameter names are somewhat descriptive but lack details on 'domain' and 'instances'.

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?

The description clearly states the tool is 'Read-only aggregate' that fans out across multiple instances and provides combined grand totals. This distinguishes it from sibling tools like 'aggregate_records' (single instance) and 'search_across_instances'.

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?

Usage is implied for cross-instance aggregation, but no explicit guidance on when to use vs alternatives like 'aggregate_records' or 'search_across_instances'.

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