ue5_compile_and_diagnose

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

With no annotations, the description carries the full burden and does well: it enumerates returned fields (asset, function, node_name, node_guid, pin hint, pitfall_ref/fix_hint), states that unparseable fields are null rather than fabricated, and warns that fix_hint is advisory. It omits the side-effect/cost profile of compiling — whether it mutates assets, blocks, or is safe to repeat — which matters for a compile operation.

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-loaded with the core action and output shape, then the routing rule, then a caveat — a sensible order with no filler. Slightly long due to the full bilingual duplication, which is conventional but does not shorten the prompt footprint.

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?

The tool has no annotations and no output schema, so the description must explain the return contract — and it does, listing every diagnostic field and the null-instead-of-fabricated guarantee. What is missing is confirmation of compile side effects and whether the blueprint must be saved/dirty beforehand.

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% with a single required bp_path already documented with an example path in the schema. The description adds no parameter-level detail beyond that, so the baseline 3 applies — the schema does all the work.

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 ('Compile a Blueprint') plus the differentiating output ('return structured compiler errors'), and names the sibling it supersedes, ue5_compile_blueprint. An agent can distinguish it from the plain compile tool 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?

Explicitly says 'Use this instead of ue5_compile_blueprint when a compile fails and you need to locate and fix the offending nodes' — naming both the alternative and the selecting condition. No inference required to route between the two compile tools.

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