diff_architectures

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

With no annotations provided, the description fully discloses behavioral traits: it states 'Pure computation — no LLM, no network. Read-only. Does not modify either spec.' This clearly informs the agent about safety and side-effect-free operation.

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 reasonably concise, with a clear purpose statement, output contents list, usage guideline, and behavior note. It is slightly verbose but still efficient, earning a 4.

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?

Despite no output schema, the description thoroughly explains what the tool returns, listing specific components of the change report. Given the complexity of nested object inputs, this provides enough context for an agent to understand the tool's full behavior.

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 description coverage is 100%, and the schema already provides clear descriptions for both parameters (old_spec_json as baseline, new_spec_json as target). The description adds no additional parameter-specific meaning beyond the schema, so baseline score of 3 is appropriate.

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 that the tool diffs two architecture specs and returns a structured change report, listing specific delta items (components, connections, cost, compliance). This distinguishes it from sibling tools like compare_provider_costs or compare_providers, which cover different comparisons.

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 includes an explicit 'When to use' section indicating the tool is appropriate for reviewing before/after spec changes for approval or ADR writing. However, it does not mention when not to use or suggest alternatives, preventing a perfect score.

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