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

Annotations already establish readOnly, idempotent, closed-world, but the description adds substantial behavior not captured there: the absence of any SQL/mutation surface, the default limit safety net, and a nuanced disclosure that next_offset=null is ambiguous on its own and must be read together with truncated, plus the min_bytes_required escape hatch for the byte budget. This is exactly the kind of beyond-annotations context that earns a 5.

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 core contract in sentence one and the safety envelope in sentence two, then paging details. Every sentence carries information, though the backtick-heavy next_offset/truncated paragraph is dense and could be tightened without losing meaning.

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 an output schema present the description need not restate return shapes, yet it usefully clarifies the response fields an agent must interpret to paginate correctly (next_offset, truncated, min_bytes_required) and explains the response_format 'got a summary but no rows' recovery path. Nothing needed to call and iterate this tool successfully is missing.

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 goes beyond it by explaining paging mechanics for offset (rows return in stored order, pass back next_offset) and by tying truncated/min_bytes_required to the max_bytes budget. It adds genuine operational meaning for offset and max_bytes that the schema text alone does not convey.

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 first sentence gives a specific verb and resource — return bounded selected rows via literal equality filters — and the second sentence sharply delineates the operation's surface (no SQL, shell, filesystem, network, extension, or mutation). That is unusually clear purpose framing, though it does not name or contrast with any of the sibling tools (e.g., inspect_dataset), so it stops short of full sibling differentiation.

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?

Provides concrete operational guidance: a safe default limit when omitted, how to page via offset/next_offset, and how to handle stored ordering (filter TIME_PERIOD or sort client-side). It does not, however, say when to reach for query_dataset rather than inspect/inspect_dataset or how to obtain a dataset_id beyond the schema's 'Id returned by stage_url'. Clear context, no explicit alternative routing.

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