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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds genuine behavioral context beyond that: the two-window comparison logic and the shape of the result (likely causes plus suggested actions). It omits any note on cost, latency, or required permissions, keeping it out of 5 territory.

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?

Two sentences, zero filler, and the core action plus the mechanism are front-loaded before the usage hint. Every clause earns its place.

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 no output schema, the description usefully sketches the return value (likely causes plus suggested actions). An agent has enough to call it correctly, though it doesn't clarify the return format or whether the diagnosis is deterministic versus heuristic.

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 all three parameters are already documented, including the SP-API enum examples for statuses. The description only reinforces the days parameter's meaning (comparison window width); it says nothing about statuses or account_id beyond the schema. 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?

States a specific verb (diagnose) and resource (sales drop), then spells out the mechanism: compares last N days against the previous period, checks account health, returns causes and suggested actions. An agent can distinguish this diagnostic tool from siblings like get_account_health or weekly_recap 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 an explicit trigger phrase ("why are my sales dropping?") that maps user intent directly onto the tool. It does not name alternatives or say when NOT to use it (e.g. versus get_account_health or weekly_recap), so it falls short of a 5.

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