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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false). The description adds genuinely non-obvious behavior: ledger rows are account/region-level with no native marketplace, surface tenant-wide for any marketplace-scoped key, and anchor to the tenant's primary marketplace, plus a UTC timestamp note. This is valuable context the annotations cannot convey, though it doesn't discuss result volume or freshness limits beyond the schema's diagnostics flag.

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 tool's purpose followed by the join semantics and the marketplace caveat. It is dense and jargon-heavy but every sentence carries distinct information; no filler or restatement of the name.

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, and the description covers the unusual scoping semantics an agent would otherwise get wrong. All 11 parameters are optional filters documented in the schema. The only minor omission is any note on default row limits or how to page, though the schema's limit/offset descriptions handle this.

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 baseline is 3. The description goes further by explaining the meaning of reference_id and date_and_time — fields surfaced by the ledger that clarify how event_type filters behave and what the returned rows represent — which adds semantics beyond the schema's terse property descriptions.

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 and resource ('Get inventory ledger movements') and enumerates the covered event types (shipments, receipts, adjustments, customer orders, returns) plus filterable dimensions. This distinguishes it clearly from siblings like get_fba_inventory, get_inventory_by_fulfillment_center, or get_returns without needing to open their schemas.

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 gives a concrete usage pattern — joining Receipts events to get_inbound_shipments via shipment_id to compute created-to-received time — which is real guidance. However, it never states when to choose this ledger over adjacent tools such as get_fba_inventory or get_returns, so the when-to-use decision is only implied.

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