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

Annotations already cover read-only, idempotent, non-destructive and closed-world, so 'Read-only' is redundant. The description earns credit elsewhere: it discloses exactly which configuration surfaces get read and, importantly, the shape of the result — named causes, sized where measurable, and an explicit 'unexplained rest' bucket, which tells the agent how to interpret partial explanations.

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?

Purpose is front-loaded in the first sentence and the supporting enumeration of inspected inputs and output shape follows in one tight block. No filler, no repetition of the title, no wasted clauses.

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?

An output schema exists, so return-value explanation is not required, but with 8 parameters at 0% schema coverage and only customer_id required, the agent must guess whether a GA4 property or conversion action is needed to get a useful answer. For a cross-system diagnostic of this complexity, that gap is material.

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 8 parameters, so the description carries the full burden and largely fails it. It never explains customer_id vs ga4_property, when to supply conversion_action_id or ga4_event, or what 'summary' vs 'full' and 'json' vs 'markdown'/'both' do; only start/end date is indirectly gestured at via 'the same dates' and 'both date bases'.

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 specific verb and a precise diagnostic question: 'Explain why Google Ads and Analytics report different conversion counts for the same dates,' then enumerates the inputs inspected (conversion window, counting, attribution, both date bases, GA4 attribution model, lookback, export scope). This clearly separates it from siblings like conversion_setup_audit or ga4_run_report, though it never names an alternative, so it stops short of an outright 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?

The phrase 'for the same dates' implies the reconciliation scenario and the read-only nature implies safe exploratory use, but there is no explicit when-to-use, when-not-to-use, or pointer to a sibling for adjacent tasks. Usage is inferable rather than stated.

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