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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description need not repeat safety traits. It adds valuable behavioral context beyond the schema: it explains the tool joins GA4, Search Console, and Bing Webmaster for holistic_bundle funnels, and that two date ranges enable period-over-period comparison. This is meaningful operational guidance not present in the structured annotations.

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?

The description is three sentences long, yet every sentence carries specific, non-redundant information: the primary use case, the two funnel modes with examples, coverage areas, and date range options. It is front-loaded with the key phrase 'Use for ordered conversion-step analysis' and contains no filler or repetition.

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 the tool's complexity (16 parameters, nested objects, output schema), the description provides a solid high-level overview: it covers both funnel types, gives example steps, and explains the date range comparison feature. It does not delve into filter expression construction or when to choose one funnel type over the other, but the output schema and property-level schema descriptions cover some of those gaps. Overall it is sufficient for an agent to understand the tool's role and basic usage.

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 coverage is only 44%, but the description compensates by giving semantic meaning to the type parameter (ordered_steps vs holistic_bundle) with concrete examples, and clarifies dateRanges usage (one window vs. two for comparison). It does not explain all 16 parameters, but the schema itself provides descriptions for several key ones (app, property, dateRanges, funnel), and the description adds examples that make the core parameters more actionable.

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's purpose with a specific verb ('get') and resource ('marketing funnel data'), and distinguishes it from siblings by detailing two funnel analysis modes (ordered_steps and holistic_bundle) with concrete examples like session_start → add_to_cart → purchase. It covers funnel drop-off, conversion paths, and acquisition-to-conversion context, making the scope unmistakable versus catalog, report, sources, or surface management tools.

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 description provides explicit context: 'Use for ordered conversion-step analysis' and lists the specific funnel types it supports. It also explains when to use one date range vs. two for period-over-period comparisons. However, it does not name alternate tools or explicitly state when not to use this tool, leaving the exclusion implicit.

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