list_partition_values_tool

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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so safety is covered. The description adds genuinely non-inferable behavior: access is over anonymous HTTPS, and a budget error must not be interpreted as a complete empty selection, which is an important partial-result caveat. It stops short of describing pagination or result ordering, which keeps it from 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?

The purpose is stated first, followed by three short, distinct caveats with no filler or repetition. It is well front-loaded and every sentence carries information, though the sentences are terse enough that the level/product semantics end up unstated.

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 and annotations cover the safety profile, so return-value and risk explanations are not required. Still, for a 7-parameter tool with 0% schema coverage, leaving five parameters including the required one unexplained is a material gap, even though the two most dangerous semantic traps (storage-label years/months, budget errors) are addressed.

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 0% across 7 parameters, so the description must carry the burden. It clarifies only year/month ("storage labels, not row-time filters") and gives a generic instruction to apply all filters; the meaning of level (the sole required param), product, project, inv_mode, and freq_mode remains completely undocumented in either location.

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 verb ("Discover") and a resource ("published L2 partition values over anonymous HTTPS"), which conveys the general idea. However, "L2" is undefined jargon and there is no differentiation from sibling listing tools such as list_parquet_files_tool, so an agent cannot confidently distinguish when this resource is the right one without reading the schema.

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 only guidance is "Apply all provided filters," which is a directive about argument handling rather than when to choose this tool. There is no mention of alternatives (e.g., list_parquet_files_tool), no prerequisites, and no indication of when-not to call it.

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