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

The description goes beyond the readOnlyHint annotation by specifying 'cost: free (pure CPU, no network)' and explaining detection methods (structural signatures for configs, headers for traces). It also explains the 'auto' mode's fallback behavior. However, it doesn't disclose potential error cases or limitations, but the annotation already signals safety.

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 well-structured and appropriately sized. It opens with the cost/read-only note, clearly states the purpose, lists supported input types in a compact list, and then offers concise pairing suggestions. Every sentence adds value without redundancy.

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?

Given there is no output schema, the description adequately explains the return value (vendor slug) and provides examples of slugs. It also contextualizes the output by noting its alignment with the 'vendor' filter. It slightly lacks discussion of when the tool might fail or return unknown, but for a detection tool this is acceptable.

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?

All three parameters have descriptions in the schema (100% coverage), so the baseline is 3. The description adds some context about input types (trace/config) and examples, but doesn't significantly enhance parameter understanding beyond what the schema already provides.

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 identifies the tool's action ('Identify the SIP product behind a piece of input') and its scope (trace or config). It distinguishes itself from the sibling 'detect_sip_vendor_from_config' by covering both trace and config, and differentiates from 'review_sip_config' by focusing on vendor detection rather than modules/risk flags.

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 explicitly states when to use the tool (for traces or configs), and pairs it with alternatives: 'search_sip_docs(vendor=<slug>)' for doc search, 'review_sip_config' when config details are needed, and 'troubleshoot_response_code(vendorHint=<slug>)' for status codes. This gives clear guidance on choosing this tool over siblings.

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