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

In addition to the read-only annotation, the description discloses the exact output semantics: per-step earliest/latest mean duration, ratio, and pass/fail run counts. It also notes the window values (1h/24h/7d/30d), making the tool's behavior more transparent beyond the annotation.

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 two sentences, front-loading the core purpose and then the use case. Though the first sentence is dense, every clause adds value and there is no filler or 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 a 2-parameter read-only tool with an output schema, the description is quite complete: it explains the kind of analysis, the exact metrics returned, and the intended diagnostic use. It does not cover edge cases like empty data, but the output schema likely addresses return structure, and the tool is simple enough that this is sufficient.

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?

Input schema covers 100% of parameters, with descriptions for both 'id' and 'window'. The description largely repeats the window values and adds no new parameter semantics beyond what the schema already provides, so 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 clearly states what the tool does: it reports the duration of each step in a browser flow monitor over a window, including trend metrics like earliest/latest mean, ratio, and pass/fail counts. This explicitly focuses on 'browser flow monitor' steps, distinguishing it from general monitor or run-level tools.

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 gives an explicit use case: 'Use this to spot a step drifting toward failure while the monitor still reports up.' This clearly indicates when to employ the tool, though it does not explicitly name alternative tools or conditions when not to use it.

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