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

Beyond the annotations (readOnly, idempotent, non-destructive), the description discloses critical behavior: result cap ('up to 8 product cards') and the mandatory thread_id propagation ('You MUST include it unchanged on every subsequent Channel3 tool call'). This is significant stateful context.

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?

Four sentences, each with a clear purpose: purpose, batching/query guidance, return shape, and mandatory thread_id rule. The thread_id warning is repeated for emphasis, which is justified given its importance. Slightly verbose but well-structured.

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?

Given the output schema and annotations, the description covers the essential aspects: purpose, usage pattern, return size, and the cross-call state requirement. No critical information 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 coverage is 100%, so a baseline of 3 applies. The description adds value by instructing to put constraints in query and reinforcing the thread_id rule, which helps the agent use parameters correctly beyond the schema text.

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 clearly states the tool's function: 'Search 100M+ products across thousands of retailers for one product type.' This is a specific verb+resource+scope that distinguishes it from siblings like browse_products or get_details.

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?

Provides explicit usage guidance: 'Call once for each distinct product type, and send independent calls together' and 'Put relevant constraints in query.' It also specifies the thread_id propagation requirement. It does not explicitly name alternative tools, but the intended use case is clear.

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