batch_place_actors_on_terrain

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

Adds real context beyond the annotations: the grounding is done by sampling the heightmap at each actor's XY rather than by line trace, and the response reports previous_z, new_z, landed_z and in_bounds per actor plus a failed[] list with errors. With destructiveHint=false already declaring the safety profile, this is solid disclosure, though it never states explicitly that actor Z transforms are mutated or whether the operation is safe to repeat.

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?

Purpose is front-loaded in the first clause, and the long inline Returns block is justified because no output schema exists. It is slightly heavy, but every element of the return shape earns its place.

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 batch mutation tool with no output schema, the definition covers the invocation method, the failure mode (failed[] with per-entry errors) and the counters needed to verify partial success. Nothing an agent requires to call and interpret the result is missing.

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 description coverage is 100%, so actors/name/label/z_offset/align are already documented in the schema. The description only reinforces the per-actor grounding semantics and says nothing extra about z_offset units or the align enum beyond what the schema states, so the 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 ('Ground many actors on the landscape in one call') and explicitly scopes it as the batch counterpart to place_actor_on_terrain ('same grounding math ... applied per actor'). An agent can distinguish it from the single-actor sibling without opening either 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?

Names the alternative tool (place_actor_on_terrain) and the condition that favors this one (many actors, one call, no line trace, no per-point python). It stops short of an explicit 'use this when / not when' rule or any exclusion, so it's clear context but not full routing guidance.

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