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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), so the bar is lower, yet the description still adds real behavior: the 100-item cap, duplicate skipping, hard stop at the plan limit, and the skipped_limit report field. It does not explain consequences of hitting the cap or whether the call partially succeeds, 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?

Two tight sentences with no filler; the batch scope and cap are front-loaded and the duplicate/limit behavior follows immediately. Every clause carries information an agent needs.

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 helpfully names the skipped_limit signal and covers the cap and duplicate handling. Minor gaps remain on failure/partial-success semantics and plan-limit preconditions, but the core calling contract is 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?

One parameter with 100% schema description coverage, so the schema already documents dataset_ids. The description's 100-item cap loosely bounds the array, but it adds no syntax or format detail beyond what the schema provides; 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 and resource with batch scope: add up to 100 datasets to the watchlist in one call. The batch framing implicitly separates it from the single-item sibling add_to_watchlist, but it never names that sibling, so differentiation is inferred rather than stated.

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 phrase 'in one call' plus the 100-item cap implies this is the bulk path versus add_to_watchlist, but there is no explicit when-to-use statement, no guidance on when to prefer the single-item tool, and no prerequisite/plan-limit context beyond 'stops at plan limit'.

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