application.launch

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

Annotations already provide idempotentHint=true, readOnlyHint=false, and destructiveHint=false. The description adds useful context beyond those annotations: it never opens a project and it requires a 'version-matched session add-on,' which communicates an important compatibility behavior. No annotation contradiction is present.

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 description is two sentences with no filler. The first sentence communicates the core behavior; the second sentence adds a critical disambiguation. Every clause earns its place.

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 zero-parameter, low-complexity tool with an output schema and supporting annotations, the description adequately covers the essential behavior. It does not detail launch failure modes or what 'configured Blender' means, but those details are not necessary for correct invocation.

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 input schema has zero parameters and schema description coverage is 100%, so the description is not required to explain parameter semantics. The baseline of 4 applies and the description introduces no conflicting or confusing parameter claims.

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 clear verb-resource pair: 'launch the configured Blender' and 'reuse a compatible Blender MCP session.' It adds scope with 'This tool never opens a project,' which helps distinguish it from project.open, though it does not explicitly name sibling tools.

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?

The description implies that this tool is used to establish or reuse a Blender session before working, but it never explicitly states 'use this when you need a live Blender session' or contrasts itself with application.status, connection.ping, or project.open. The negative boundary ('never opens a project') gives some guidance, but leaves the main usage decision to inference.

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