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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, covering safety. The description adds behavioral context about the output: the key indicates similarity, not exact match, and records with the same key 'likely share both a similar company name and address.' It also discloses the cost, which is useful operational info. This goes beyond annotations without contradicting them.

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 three sentences with no filler. It front-loads the core function, then explains the output meaning, then gives the use case and cost. Every sentence earns its place.

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 two-parameter tool with no output schema, the description adequately explains what the tool does and what the output represents (a combined key). It mentions the cost and use case. It doesn't specify the exact response format, but the 'generate a key' phrasing implies the output. This is sufficient for a simple tool, so a 4 is appropriate.

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 already provides full descriptions and examples for both company and address, so schema coverage is 100%. The description does not add any parameter-specific details beyond what the schema provides; it merely restates the general purpose. Thus, it stays at the baseline of 3 for high coverage.

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: generating a combined similarity key from company and address. It also names the specific use case (business-location deduplication) which distinguishes it from siblings that handle company or address separately. The verb 'generate' and the resource 'combined key' are precise.

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 gives a clear context: 'Ideal for business-location deduplication across vendor, supplier, and account datasets.' This tells the agent when to use it, but it doesn't explicitly mention alternatives or when not to use it. Since the use case is clear but no exclusions are given, it scores a 4.

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