Group By User Agent

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

No annotations are provided, so the description carries the full disclosure burden, and it delivers almost none: no return shape, no pagination behavior, no statement of the facet_size cap (schema allows up to 300), and no note on defaults (query '*', window '-1h'). The 'thin wrapper' note usefully signals that behavior mirrors field_facets, but that is the only behavioral context offered.

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?

A single front-loaded sentence that states the operation, the dimension, the scope, and the underlying primitive with zero filler. Nothing could be removed without losing meaning.

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 undocumented parameters, no annotations, and no output schema, the description is far too thin to let an agent invoke this confidently. The unspecified user_agent_field parameter in particular leaves ambiguity about what is actually being grouped, and nothing explains the facet_size limit or defaults.

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 5 parameters, so the description must compensate and largely does not. 'Query/time range' loosely maps to the query and window params, but account, facet_size, and especially user_agent_field (which presumably controls the field being faceted) are entirely unexplained anywhere.

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 operation (facet counts), a specific dimension (User-Agent), and the scoping inputs (query/time range), which cleanly separates it from siblings like group_by_ip and group_by_path. It also names its underlying primitive, field_facets, so an agent knows exactly what it wraps. It stops short of a 5 only because it doesn't contrast itself against field_facets as an alternative.

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?

The parenthetical 'thin wrapper over field_facets' implies the agent should use field_facets directly for non-User-Agent facets, which is a usable routing hint. But there is no explicit when-to-use/when-not-to-use statement and no mention of prerequisites such as a valid account or time window. Usage is left to inference.

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