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

Beyond the readOnly/idempotent/closed-world annotations, it discloses substantive behavior: private, unlisted, hidden, and API-only objects are excluded before page limits, and a range exceeding 50,000 pages fails explicitly. This is exactly the kind of behavioral context annotations cannot carry.

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?

Front-loaded with the two modes, then supporting constraints. Four sentences, each carrying distinct information (modes, exclusions, alternative consumer, failure behavior). Dense but not padded.

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?

With no output schema, the description carries the burden of explaining returns; it does this for the range mode (canonical paths and modification times) though the list mode's return shape is only implied. Annotations cover the safety profile and the exclusion/failure behavior is stated, leaving it largely complete.

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%, so the baseline is 3. The description adds meaning by correlating the parameters with the two modes (pass a range to read canonical paths; omit both to list ranges) and by noting the boundaries come from the sitemap index, going slightly beyond the schema's per-field descriptions.

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 specific verbs and resources: listing fixed public-page keyspace ranges versus reading canonical paths and modification times. It clearly describes two operating modes. It does not distinguish from siblings, but the sibling list is heterogeneous (block, send_dm, etc.) with no apparent alternative, so differentiation is largely moot.

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?

It explains the two modes (no arguments to list ranges vs. passing a range to read content) and routes a distinct consumer elsewhere ('Website crawlers can read /sitemap.xml instead'). It gives the failure condition for oversized ranges and the remedy (finer index partitions). No explicit when-not for agent callers beyond the crawler note.

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