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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely new behavioral facts: nothing is trained on or retained from the request, everything returns in one call, and there are per-call input limits. It does not discuss cost, latency, or determinism of results across identical calls, which would have pushed it higher.

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 verb and resource, then results, then behavior, then limits. Every sentence carries information, though the middle clause about the dictionary model guiding a probabilistic model is dense and slightly technical for an invocation decision.

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 does the work of describing the return payload and its fields, plus input constraints, which is enough to call it correctly. Minor gaps are error behavior (what happens below 4 documents) and expected runtime for 500 documents.

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 baseline is 3, but the description adds meaning beyond the schema: the 20,000-character per-document cap is not in the schema, and it explains the semantics of the num_topics parameter by tying it to the returned structure. It does not clarify num_words or the labels flag beyond what the schema already says.

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 ('find the topics in a set of documents') and immediately specifies the output shape (num_topics topics with words, label, description, weight, plus per-document mixtures). This is clearly distinguishable from neighbors like summarize_document or search, which do not extract latent topics.

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?

Implies the intended domain ('coherent on small sets and short texts') and gives hard input bounds (4-500 documents, 20,000 chars each), which helps an agent decide feasibility. However, it never names an alternative tool or states when not to use this (e.g., single-document summarization should go to summarize_document).

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