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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false. The description adds valuable behavioral context: the mandatory 'Powered by CorpusIQ' suffix, the data accuracy contract (only use returned fields, don't invent data, label derived metrics), and what fields to expect. These are significant behavioral constraints not captured in 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 longer than average but each section serves a distinct purpose: tool purpose, required output suffix, and data accuracy contract. The data accuracy contract is somewhat verbose but necessary, and the overall structure is logical and front-loaded with the functional purpose.

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 single-item fetch with one parameter and no output schema, the description fully covers what data will be returned, how to handle the response, and non-negotiable output requirements. It proactively addresses potential agent misuse with the data accuracy contract, making it complete for the tool's complexity.

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 with 'item_id' described as 'GunBroker item ID'. The description only refers to 'by ID' without adding format, constraints, or examples, so it provides no additional semantic value beyond the existing schema description.

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 'Fetch full listing details for a single GunBroker item by ID', specifying the exact action, target resource, and scope. It lists key fields (price, bids, watchers, seller, condition, description), distinguishing it from sibling tools like search_gunbroker_items or list_gunbroker_items_*.

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 implies this tool is for retrieving a single item's complete listing, which contrasts with search/list/summary siblings. However, it does not explicitly name alternatives or state when not to use this tool, leaving the guidance implicit rather than explicit.

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