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

The description adds behavioral context beyond annotations by explicitly stating idempotency ('Idempotently create or reconcile') and the reconcile semantics, which reveals that the tool may adjust an existing route rather than only creating. The annotations already mark idempotentHint=true, so the extra detail about 'reconcile' enhances transparency without contradicting structured data.

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 a single, front-loaded sentence that efficiently combines action, prerequisites, and idempotency. Every word contributes meaningful context with no redundancy, earning a top score for conciseness.

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 (2 required params, no output schema, strong annotations), the description adequately covers its purpose and prerequisites. It does not mention error conditions or response details, but these are often unnecessary for a setup tool when the schema and annotations provide sufficient context. A slightly more explicit mention of what 'apply' results in could push it to a 5.

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% coverage for both parameters with clear descriptions ('Setup-session ID' and 'Secret returned at creation'). The description does not add parameter-specific meaning beyond what the schema states, so it meets the baseline but does not exceed it.

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 action ('Idempotently create or reconcile') and the resource ('the route'), with specific prerequisites that frame the tool's scope. It distinguishes itself from siblings like 'start_review_router_setup' by referencing the post-setup phase, making the purpose unambiguous.

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 clear context for when to use the tool: 'after the person completing setup signed in, claimed the current intent, and connected both providers.' It does not explicitly name alternatives or exclusions, but the prerequisites imply a natural workflow order, which is a clear usage guideline.

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