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

readOnlyHint already covers safety, so the description focuses on richer context: the default is Seller Central data unless a channel is passed, and the agent must never sum 3P and 1P figures itself. It also discloses that accounts can span multiple workspaces (agency/clients), which an agent could not infer from annotations or schema. Slightly indirect because much of the behavior described belongs to the calling tools rather than this one.

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 with the return-field inventory, then the channel definitions, then the cross-tool rule; each block earns its place. It is dense and long for a list tool, and the 3P/1P summation warning could be shortened, but nothing is redundant.

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 exists, and the description compensates by listing every returned field including nested marketplace country/domain and workspace membership. For a discovery tool that gates the channel arguments of several sibling tools, it supplies everything needed to call it and use the result correctly.

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?

Only one optional parameter (`reason`), and the schema documents it fully at 100% coverage, so the baseline for a near-zero-parameter tool applies. The description wisely spends its space on return values and channel semantics instead of repeating the `reason` instructions.

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 ('List the seller's Amazon accounts you can query') and enumerates exactly what comes back (id, name, region, channel, marketplaces, workspaces). This is unmistakably distinct from the query_* and list_metrics siblings in the same namespace.

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?

Tells the agent how to read the `channel` field and explicitly names the downstream tools it governs (query_metrics, find_movers, explain_movement) plus the exact override syntax channels=['VENDOR'] / ['SELLER','VENDOR']. It also routes workspace-level disambiguation to the `workspaces` field and the `accounts` filter of other tools.

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