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

Beyond the readOnlyHint annotation, the description adds valuable context: 'cost: free (pure CPU, no network)' and 'read-only'. It also discloses the heuristic nature, expected return fields, and limitations ('detect-only', does not extract directives or flag risks). This goes well beyond 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 concise and front-loaded with cost/read-only context. Each sentence adds substantive value: purpose, output, usage, and tool pairings. No redundancy or filler.

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 the tool's moderate complexity, the description is complete enough. It covers what the tool does, what it returns, when to use it, and how it relates to sibling tools. Even without an output schema, the return fields are specified. The cost/network behavior adds essential context.

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 100% description coverage for both parameters, so the baseline is 3. The description implicitly refers to the config blob input ('attaches a SIP config file') and mentions structural signals like 'loadmodule syntax, route blocks, profile elements', but does not significantly enhance parameter semantics beyond the schema descriptions.

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: detect a SIP vendor from a config file, returning the vendor slug, confidence level, and structural signals. It explicitly distinguishes itself from the sibling `detect_sip_stack` by being a 'heuristic-only sibling scoped to vendor configs', and clarifies it does not extract directives or flag risks.

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 provides explicit usage guidance: 'Use this when the user asks "what is this config?" or attaches a SIP config file.' It also explains pairing with `review_sip_config` and `search_sip_docs`, and explicitly states what the tool does NOT do, setting clear boundaries vs alternatives.

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