set_reactions

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

Discloses the critical behavioral trait that it overwrites existing reactions rather than appending — a nuance not captured by the readOnlyHint/destructiveHint annotations. It also states the return value '{ ok, nodeId }', adding transparency beyond what annotations offer.

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?

Two sentences only. The first sentence states the core behavior; the second packs the data structure, usage context, alternative, and return value. Every phrase earns its place with no filler or redundancy.

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?

Despite the lack of an output schema, the description documents the return value, the primary use case, the overwrite behavior, and the alternative tool. For a simple 2-parameter tool, this is fully self-contained and leaves no major gaps.

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?

The schema already documents both parameters, but the description adds concrete JSON examples for trigger ({ type: 'ON_CLICK' }) and actions ({ type: 'NODE', destinationId, navigation, transition }), making the data shape more tangible. This reinforces the schema without repeating it verbatim.

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 opens with 'Replace all of a node's prototype reactions' — a specific verb, resource, and scope. It explicitly contrasts with appending ('overwrites existing reactions rather than appending') and distinguishes from remove_reactions, making it clear what this tool does and how it differs from siblings.

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?

Provides explicit guidance: 'Best used to round-trip get_reactions output' tells the agent exactly when to use this tool. It also names an alternative, 'to clear all reactions instead use remove_reactions', giving a clear when-not-to-use and an exclusion.

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