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

Annotations already cover readOnly, idempotent, openWorld and non-destructive, so the safety profile is settled. The description adds genuine context beyond that: the catalog spans ~130 schemas, table names are survey-specific, and an unknown name fails hard rather than returning empty. It does not discuss pagination limits or result size, but the limit parameter covers that.

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 purpose, then the usage directive, then concrete table-name examples that make the naming convention tangible. Every sentence carries weight, though the closing 'AUTHORITATIVE' claim is more emphasis than information.

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 usefully states what is returned in each mode (table descriptions and row counts, or columns with units and descriptions), and the query-error warning sets expectations for failures. It is complete enough to call correctly; only result-format specifics are left implicit.

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% and the parameter descriptions already explain limit defaults/max, the fully-qualified table format, and that omitting schema lists everything. The description restates the mode switch (table returns columns instead of tables) but adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb (list) and resource (schemas/tables in NOIRLab Astro Data Lab) and explicitly covers the two modes: listing tables with description and row count, or listing columns of one named table. An agent can distinguish this from datalab_query purely from the description.

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?

"CALL THIS BEFORE WRITING A QUERY" gives explicit, actionable timing, and it explains the cost of skipping it (a guessed name is a query error, not an empty result). It does not explicitly name datalab_query as the follow-on alternative or state a when-not condition, keeping it just short of a 5.

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