Set ambient

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

Annotations already declare readOnly=false, idempotent=true, destructive=false, so the safety profile is covered. The description adds real behavioral context beyond that: null drops a key to the FDS default (with the default values), `extra` is written verbatim and replaces same-KEY entries, and the GPU engine consumes all three fields.

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?

Three tight sentences, front-loaded with the primary keys before the `extra` escape hatch and the null rule. The bracketed rules footer (GEN-016, SIM-002) is compact but slightly cryptic out of context.

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?

For a 4-parameter, no-output-schema setter with full schema coverage, the description supplies the defaults, the null-drop fallback, the verbatim-write contract, and the downstream consumer, leaving nothing an agent needs in order to call it correctly.

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 would be 3, but the description adds meaning the schema lacks — the collective null semantics ('pass null for a key to drop it and fall back to default') and the verbatim replacement behavior of `extra` are stated at the tool level rather than per-field.

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+resource ('Set the ambient conditions') and enumerates exactly which &MISC keys are written (TMPA, HUMIDITY, Y_CO2_INFTY), so an agent can distinguish it from siblings like set_run_options, set_numerics, or set_time without opening 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?

Gives clear conditional guidance on parameter routing ('use `extra` for any other &MISC key', 'pass null to drop a key and fall back to the FDS default') and routes to bulc_knowledge_search for the cited rules. It does not, however, name alternatives or state when NOT to use this tool versus other set_* tools.

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