Set fds properties

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

Beyond the annotations (idempotent, non-destructive, non-readonly), the description discloses key semantics: fds_override fields are MERGED, whereas spr_spray_override REPLACES prior overrides. That merge-vs-replace distinction is exactly the kind of behavior an agent would otherwise get wrong.

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?

Well front-loaded: verb+resource, then merge semantics, then the override catalog grouped by device type. The key list is long but each entry earns its place for an open-ended object schema; it is dense rather than padded.

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 flexible, nested, no-output-schema mutation tool, this covers the essentials: what mutates, how it merges, a pointer to read-first and an alternative tool. The only minor gap is no statement of return/confirmation behavior, which the absence of an output schema makes forgivable.

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?

With only 60% schema coverage and an opaque free-form fds_override object (additionalProperties: true), the description does the heavy lifting: it enumerates valid keys per device category and supplies units for otherwise cryptic fields (k_factor L/(min·bar^½), operating_pressure bar, flow_rate L/min, particle_diameter µm) plus a nested-value example.

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: 'Update an obstacle's Runtime FDS Properties,' and clarifies it writes runtime FDS state (fds_override, is_fire_source/hrrpua/surf_ids). It stops short of explicitly differentiating itself from siblings like update_obstacle or shape_set_item_fds_props, but the scope is unmistakable.

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 real usage direction: 'Read current values first with get_object_properties' establishes a prerequisite read step, and it routes the sprinkler spray case to an alternative ('prefer spr_set_head_spray'). It does not explain when to choose this over update_obstacle, but the operative context is clear.

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