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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds value beyond this by disclosing the specific data returned (discount percentages, negotiation windows, leverage points, auto-renewal risk flags, script) and provides a concrete example with numbers, giving the agent a clearer expectation of the tool's output richness. It could go further by noting any limitations (e.g., coverage gaps for niche vendors) but this is not required.

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 concise and front-loaded: it opens with the usage trigger, then lists the returns, and ends with a concrete example and source. Each sentence serves a purpose with no fluff or repetition. The structure is ideal for quick agent parsing.

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?

With no output schema, the description effectively explains what the tool returns by enumerating key data points and providing an example. It covers the main aspects an agent needs to know for invocation and result interpretation. It could be more complete by mentioning error handling or data availability for unknown vendors, but given the simplicity of a single parameter, this is a minor gap.

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 schema provides only vendor_name as a required string with no description (0% schema coverage). The description compensates by stating the tool works 'for any vendor' and gives an example with 'Salesforce', making it clear that vendor_name is the vendor's name. While not a formal parameter description, it adds meaningful context beyond the bare schema.

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 purpose: 'Use when preparing to renew or renegotiate a SaaS contract' and lists specific outputs ('returns typical discount percentage, best negotiation windows, leverage points, auto-renewal risk flags, and a negotiation script'). It distinguishes itself from sibling tools by focusing on negotiation-specific intelligence for any vendor, not just benchmarks or market analysis.

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 provides explicit when-to-use guidance: 'Use when preparing to renew or renegotiate a SaaS contract.' This clearly indicates the primary use case. However, it does not mention when not to use it or name alternative tools, so it misses the full 'when-not/alternatives' criteria for a 5.

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