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

With no annotations, the description carries the full burden and does so: it discloses pricing (10 free questions then per-question charge), org-level billing exemption, the 3-free-question Deep Review variant, the insufficient_funds error and required user messaging, and the aggregate/no-individual-quotes constraint on answers. This is exactly the cost, failure, and output-shape information an agent needs before invoking a billable tool.

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?

Four tight paragraphs that are front-loaded with the core purpose and then layered by eligibility, pricing, and return shape. A few phrases repeat ('as on the web', the Deep Review pricing restated) and the returns line duplicates information the agent could infer, keeping it just short of a 5.

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?

No output schema exists, yet the description specifies the returned fields (sim_id, answer, chat, charged_credits, questions_remaining_free, credits_per_question) and the two chat modes. Combined with the error list and billing rules, an agent has everything needed to call this correctly and to explain the result to a user.

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 the baseline is 3, but the description adds real meaning: sim_id must be a *completed* study of a supported type (with the supported set enumerated), and the question length limit differs for Deep Review screenings, which is also noted. Only minor duplication remains.

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 ('ask a follow-up question about a completed study') and immediately scopes it as the study's moderator chat answered from the study's own results, not a new data collection. It is clearly distinguishable from siblings like run_focus_group, run_debate, and screen_creatives, which are named as the tools that produce the studies this one queries.

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?

Explicitly enumerates where it works (Pulse studies from run_focus_group/run_debate, Screening Room Deep Reviews) and where it does not (compares, Quick/Balanced screening, Ads Labo, pricing, MaxDiff), including the exact failure mode error='not_supported' with no charge. It also routes Deep Review follow-ups to the analyst chat, giving the agent a clear alternative path.

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