runtime_set

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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the mutation/safety profile is covered. The description adds genuinely useful behavioral context: automatic type coercion of the value argument and the read-back of the engine-reported value, which the annotations do not convey.

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-loads the core action in the first sentence, then gives conversion examples, then the return value. Three tight sentences with no filler; only minor density from the inline examples.

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 covers the return ('the value the engine now reports'), the mutation semantics, and the tricky value-coercion rules, while the schema fully documents node/property/object_id/session_id. Nothing an agent needs to call it correctly 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 baseline is 3, but the description meaningfully enriches the opaque `value` parameter ('New value') with concrete conversion formats — [1,2] or 'Vector2(1, 2)', '#ff0000' for Color, res:// paths for resources. That is real added meaning beyond the schema.

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 (change) and resource (a property on a node in a running game), plus the read-back behavior. However, it does not distinguish itself from siblings like runtime_eval, which an agent might reasonably assume can also mutate state.

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?

No when-to-use or when-not-to-use guidance, and no mention of alternatives such as runtime_eval or runtime_inspect. The conversion examples imply usage but never state the condition that selects this tool over its siblings.

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