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

Annotations already declare readOnlyHint=true and idempotentHint=true. The description adds context about the return content (rules, pricing, capacity, active buy count, allowlists/blocklists) and current utilization, which is useful for understanding the tool's behavior.

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 organized into tool_description, when_to_use, combination_hints, and output_format sections. It is concise, though the output_format section slightly repeats the tool_description.

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?

For a simple read tool with one parameter, the description covers what it does, when to use it, and what it returns. The output_format mentions full slot details with rules, pricing, capacity, and active buy count, making it complete.

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?

The input schema has 100% coverage for the single parameter inventory_id, described as 'Inventory slot UUID'. The description does not add additional parameter semantics, but the schema is sufficient.

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: 'Get detailed information about a specific publisher inventory slot, including rules and active buy count.' This verb+resource structure distinguishes it from sibling tools like get_product or get_campaign_report.

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 'when_to_use' section explicitly says 'After list_inventory to get full slot details before bidding' and 'Check capacity before create_media_buy', providing clear usage context and sequencing with sibling tools.

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