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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: compilation uses the same engine as the API, tests run against in-memory data, it returns diagnostics with JSON pointers, reads/writes analysis, and failure reasons, and it incurs no cost and sees no data. This is rich but does not cover auth requirements or rate limits.

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?

Three sentences, front-loaded with the core action, followed by return details and a safety/cost note. Every sentence earns its place with 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?

An output schema exists, so return values need not be fully explained. The description nevertheless summarizes key outputs (diagnostics, reads/writes, failure reasons), covers the execution model, and aligns with annotations. Given the 3-parameter schema with full descriptions, nothing critical is missing for correct invocation.

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%, so the baseline is 3. The description adds meaning by specifying the document format version (flows-v1) for the flow parameter, which the schema only calls 'The flow document'. It does not clarify the knownLists parameter, but the schema already documents it, so the added value is moderate.

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 states a specific compound verb (compile and run tests) on a specific resource (flow document, flows-v1) using the same engine as the API. It distinguishes itself from sibling tools like check_write_rules or validate_sync_document by focusing exclusively on flow compilation and test execution.

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?

Usage is implied: the tool is for checking a flow document and its tests. However, the description provides no explicit when-to-use or when-not-to-use guidance, nor does it name any alternative tool or condition under which another sibling should be preferred. 'Costs nothing and sees no data' hints at safe usage but is not a routing guideline.

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