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

Annotations already assert readOnlyHint=true and destructiveHint=false, so the low bar is met. The description adds valuable context: 'makes no identity or causality claim' informs the agent about interpretive limits, and 'bounded processor' plus 'analyzes only the JSON you provide' indicates statelessness and no data retention. Pricing and payment method ($0.05/call, x402 USDC on base) are also disclosed, beyond what annotations capture. Not a 5 because it doesn't describe the exact output shape or whether any logs are kept, but it's solid.

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 exactly two sentences. The first sentence states the core function and use case; the second adds key caveats (bounded, no identity/causality claims) and monetization. No filler, no repetition of schema details. Highly scannable and front-loaded.

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?

For a 2-parameter tool with no output schema, the description is nearly complete. It explains what the tool does, its processing boundary, and pricing. The only gap is that it doesn't describe what the output looks like (e.g., a transition count list or aggregate measures). Since there is no output schema, one could argue the description should hint at the output format, but the tool name and 'Measure... transitions' imply a quantified result. Given the strong schema and annotations, this is a minor omission, not a serious shortfall.

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 coverage is 100%: the schema richly describes both schemaVersion and sequences, with per-field descriptions (e.g., 'Two to 30 opaque IDs... repeated step IDs are allowed because order and loops are meaningful'). The description adds no new parameter-level semantics beyond reinforcing that sequences are 'buyer-supplied' and 'opaque.' Since the schema already carries the load, a baseline 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 opens with a specific verb and resource: 'Measure ordered adjacent transitions in buyer-supplied opaque sequences...' This clearly distinguishes it from sibling tools like cooccurrence-analyzer or cross-tabulator, which analyze different aspects of sequences. The scope (workflow, funnel, journey analysis) and the opaque-sequence constraint further refine its purpose.

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 tells when to use it: when you need to analyze ordered adjacent transitions in sequences for workflow/funnel/journey analysis. It also implies a boundary via 'bounded processor... analyzes only the JSON you provide,' which hints that it is not for cross-request or external data. However, it does not explicitly contrast with alternatives (e.g., 'use cooccurrence-analyzer for non-adjacent pairs'), so it misses the 'when-not-to-use' guidance that would earn a 5.

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