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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description does not need to prove the operation is safe. It adds valuable non-obvious behavior beyond annotations: the tool is free of per-call credits and monitoring endpoints do not consume credits. It also clarifies what statuses and fields the response contains.

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 compact and well-structured: purpose first, then usage workflow, then a cost note. Every sentence adds practical value, and the key workflow is front-loaded. No filler or repetition of schema content.

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?

Even without an output schema, the description names what each item contains, explains how to filter and debug, notes the free-of-charge behavior, and links the item_id to a downstream use. Given the tool's moderate complexity, this is sufficient for an agent to select and 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 100%, so the schema already documents all parameters. The description adds contextual meaning: group_id comes from list_bulk_jobs, status='failed'/'invalid' is for debugging partial_success jobs, and search_key finds a specific ASIN in a large job. This goes beyond what the schema alone provides.

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: 'Inspect the individual items inside a bulk job' and enumerates exactly what each item exposes (input value, status, error message, credit cost, completion time). It clearly differentiates from list_bulk_jobs by focusing on item-level inspection rather than job-level summaries.

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 explicit when-to-use guidance: debug a job after list_bulk_jobs shows failed_items or invalid_items > 0, filter by status='failed' or 'invalid', and use search_key to locate a specific ASIN. It also ties the resulting item_id to a downstream Data Service call, so an agent knows exactly how to proceed.

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