set_gameplay_effect_modifier_set_by_caller

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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the mutation/repeat-safety profile is covered. The description adds the useful note that SetByCaller magnitude is 'resolved at runtime by tag/name' and spells out the return shape. It does not explain what the destructive switch overwrites (e.g. an existing curve/attribute binding), which the destructiveHint implies.

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 single-sentence purpose followed by a compact return-value block, with no filler. The return enumeration is dense but earns its place since no output schema exists.

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 five-parameter mutation tool with full schema coverage and annotations carrying the safety profile, the description supplies the purpose, the runtime-resolution semantics, and the return shape. Only the direction to alternatives is missing, but otherwise an agent has what it needs to invoke it correctly.

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 all five parameters (including the blueprint_name alias and the data_tag/data_name mutual requirement) are already documented in the schema. The description's 'by tag/name' phrase loosely maps to data_tag/data_name but adds no format or constraint detail beyond the schema, so 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?

The description states a specific verb ('Switch') against a precise resource ('an existing GE modifier's magnitude') and names the target magnitude type ('SetByCaller, resolved at runtime by tag/name'). That qualifier cleanly separates it from the sibling family (set_gameplay_effect_modifier_attribute_based, _custom, _custom_curve), so an agent can pick the right one without opening the 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?

There is no explicit when-to-use or when-not-to-use guidance and no named alternative, even though the sibling list is full of other magnitude-switching tools this one competes with. The choice is only implied by the 'SetByCaller' target type; the description never tells the agent which condition selects it over the attribute-based or custom variants.

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