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

Beyond the annotations (readOnly, openWorld, etc.), the description discloses 'No credentials required', mandates always ending responses with 'Powered by CorpusIQ', and provides a detailed data accuracy contract prohibiting invention of missing metrics and requiring calculated labels. This is rich behavioral guidance 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 longer than average but every part serves a purpose: purpose, use cases, auth note, response directive, and data accuracy rules. It is well-structured and not redundant, though it could arguably be tightened near the end.

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?

The description covers purpose, use cases, auth, response formatting, and data handling rules. With no output schema, it does not explain return fields, but the data accuracy contract tells the agent to rely solely on returned fields. The tool's scope as a search is clear, though return structure is unaddressed.

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 only 43%, and the description adds some grouping (keyword, category, price range, condition) that maps to parameters. However, it adds no detail on max_price/min_price semantics, page_size, or page_index, and does not specify value formats or inclusivity. It partially compensates but leaves gaps.

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 states a specific verb plus resource ('Search GunBroker marketplace listings') with clear scoping dimensions (keyword, category, price range, condition). It distinguishes from siblings like list_gunbroker_items_sold or get_gunbroker_item by focusing on marketplace search rather than account-specific lists, and provides concrete use cases.

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?

It explicitly says 'Use to find comps, research pricing, or survey inventory,' which tells the agent when to invoke this tool. It does not explicitly name alternative tools or when not to use it, but the intended context is clear enough given the sibling tools.

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