add_call_library_function

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

Annotations only declare the safety profile (readOnly=false, non-idempotent, non-destructive); the description goes well beyond by disclosing that the tool compiles, that pins are returned inline so no follow-up read is needed, and a concrete failure mode where a misnamed parameter aborts only that batch step and leaves dependent connections reporting 'Target node not found'. That is exactly the kind of non-obvious operational context annotations cannot carry.

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?

The core capability and the sibling routing rule are front-loaded, and the return-shape sentence is efficient. The TRAP sentence is long and is really about build_blueprint_graph rather than this tool, which slightly blurs the focus, but each sentence carries usable information.

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 9-parameter Blueprint mutation with no output schema, the description supplies purpose, alternatives, prerequisites, a failure mode, and an explicit return shape. The only real gap is the target-Blueprint resolution when blueprint_name/graph_name are omitted, which an agent must infer.

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% (all 9 parameters documented, including the detailed PIE-refusal semantics of `force`), so the baseline is 3. The description restates `function_library` and `function_name` formats but adds little beyond what the schema already says, and never clarifies how the target Blueprint is resolved when `blueprint_name` is omitted.

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?

The description gives a specific verb+resource ('Add a call node for a STATIC library function') and explicitly bounds the resource type (engine libraries like KismetMathLibrary/GameplayStatics, /Script/Engine classes, or user BlueprintFunctionLibrary assets). It also differentiates itself from the nearest sibling by name and node_type ('Prefer add_graph_node node_type="call_function" when the target is a member function of an actor/component').

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?

It gives a clear routing rule against add_graph_node and a prerequisite workflow ('Plan the wiring with get_function_pins ... WITHOUT creating anything'), plus the batch-parameter naming caveat. It does not, however, distinguish itself from the other graph-node siblings in the same family (call_function, call_library_function, add_parent_call_node), so the exclusion set is incomplete.

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