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

Annotations already mark the operation as idempotent and non-destructive, so the description's job is to add behavioral depth. It does so thoroughly: manual mode means nothing is auto-published, pause stops product sync, status differs per mode ('updated' vs 'paused'), and confirmation should be done via marketplace_status or get_marketplace. This goes well beyond the structured annotations.

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?

The description is dense but every sentence earns its place. It front-loads the purpose, then moves logically through mode definitions, manual trigger alternatives, return values, and parameter provenance. No filler or repetition exists.

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 supplies the return shape and status semantics. It also covers the manual-mode flow, confirmation step, and the conditional project_id requirement. Given the tool's complexity and the low schema coverage, the description leaves nothing an agent needs to invoke it 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?

Schema description coverage is only 33% (just the mode enum), yet the description adds rich semantics for all three parameters. It explains each mode's behavior, says marketplace_id comes from list_marketplaces, and clarifies that project_id is optional but may become required depending on the customer context. This fully compensates for the sparse schema.

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 resource: 'Set how a marketplace synchronizes products to its channel.' This clearly identifies the tool's focus—product sync mode—and differentiates it from siblings like set_marketplace_order_mode and set_marketplace_name. The three modes are explicitly defined, leaving no ambiguity about scope.

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 provides clear context for when to use each mode, including the note that 'manual' is the safe way to activate for a test. It also names alternatives for pushing items manually (run_marketplace_item_action and run_marketplace_operation) and suggests reading marketplace_status or get_marketplace to confirm the applied mode. It does not explicitly exclude other tools like pause_marketplace, but the guidance is still strong.

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