funnel_report

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

Annotations already declare read-only, idempotent, non-destructive behavior, so the safety profile is covered. The description adds genuine domain behavior beyond that: funnels are resolved by name or id, steps must be completed in order, and a visitor's segment is taken from their entry-step event. The entry-step attribution rule is non-obvious and valuable; only return shape and any pagination/limits are absent, and an output schema exists anyway.

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 core purpose, then the matching rule, then the optional segment behavior. No filler, no repetition of the tool name, and each sentence adds distinct information.

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?

Given an output schema exists, the description need not explain return values, and it provides the funnel-resolution rule and segment semantics that the schema omits entirely. It is close to complete for calling the tool, with the only soft spot being no explanation of the 'days' window or guidance on when to prefer this report over sibling reporting tools.

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%, so the description carries the full burden for three parameters. It explains 'funnel' (match by name or id) and 'segment_by' thoroughly, including concrete examples and the entry-step attribution semantics, which goes well beyond the bare schema. Only 'days' (default 30) is left unaddressed, which is a small but real gap.

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 opens with a precise verb+resource: 'Conversion report for a funnel (match by name or id).' An agent can immediately tell this produces funnel conversion output, distinct from siblings like retention_report, goal_report, and breakdown. It stops short of naming a sibling to route against, so it earns a 4 rather than a 5.

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?

It gives conditional guidance for one parameter ('Pass segment_by ... to compare conversion per segment'), which is real when-to-use advice. However, it never says when to choose funnel_report over siblings such as breakdown, compare, or retention_report, and no prerequisites or exclusions are stated. Usage is implied rather than framed against alternatives.

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