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

With no annotations, the description carries the full burden and does so: it discloses the three-tier source hierarchy, which tier is canonical vs. slightly inflated vs. last resort, that a `_warning` is emitted on the pixel fallback, that channels use Triple Whale attribution when connected, and that pixel counts undercount. It also flags the important trap of not quoting `_pixelFunnel.cvr` as the store CVR.

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?

Front-loaded and dense but nearly every sentence carries routing or source-hierarchy information. The one cost is redundancy: the 'canonical CVR comes from get_metrics_comparison / never quote _pixelFunnel.cvr' rule is stated at least three times (body, 'Use for' clause, Notes), which dilutes the signal.

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?

No output schema and no annotations, so the description must explain the return shape itself, and it does: it enumerates the `funnel`, `_pixelFunnel`, `channels`, ROAS/MER, and `dailyTrends` blocks with their sub-fields. Nothing an agent needs to interpret or safely quote results is missing.

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 100%, so the three date/pagination params are fully documented in the schema. The description adds no parameter-level syntax, formats, or default semantics beyond what the schema already states. Baseline 3 is appropriate when the schema does the heavy lifting.

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?

Opens with a specific verb+resource ('Get marketing performance dashboard') and immediately scopes it with 'INCLUDING the canonical checkout funnel.' It explicitly distinguishes itself from siblings by naming get_analytics, get_store_summary, and get_metrics_comparison, so an agent can route correctly without opening any schema.

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?

Gives explicit trigger phrases ('checkout funnel', 'where do customers drop off') and an explicit prohibition against manual stitching, plus a routing rule for the CVR figure ('for the actual CVR figure use get_metrics_comparison'). This is when-to-use, when-not-to-use, and named alternatives in one pass.

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