List Python packages available to Blender's interpreter, including sys.path and the project-local directory for installing new ones.
List the Python packages Blender's own interpreter can see, with sys.path and the project-local directory new packages go into.
| Name | Required | Description | Default |
|---|---|---|---|
| response_format | No | 'markdown' for readable output, 'json' for raw structured data. | markdown |
Changes observed during successful MCP inspections.
v4.4.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is established. The description adds useful behavioral context beyond annotations by specifying that the tool reports sys.path and the project-local directory where new packages go, which helps the agent understand what the listing exposes.
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 a single sentence that front-loads the core action and resource, then appends the two useful output details. There is no wasted text or repetition of schema 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?
This is a low-complexity read-only list operation with one well-documented optional parameter and annotations covering behavior. The description explains what will be listed (visible packages, sys.path, project-local directory), which is sufficient given the absence of an output schema.
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% for the single optional response_format parameter, which is fully documented in the schema. The description adds nothing about parameters, so the baseline of 3 is appropriate.
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 uses a specific verb ('List') against a clearly defined resource ('Python packages Blender's own interpreter can see') and adds what the output includes (sys.path, project-local directory). It is easily distinguished from siblings like blender_install_package and blender_list_installed_addons because it targets packages visible to Blender's interpreter, not addons or installation operations.
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?
No explicit guidance is given for when to use this tool versus alternatives such as blender_python_env, blender_list_installed_addons, or blender_install_package. The purpose is clear, but the agent is left to infer the appropriate selection context without any exclusions or routing hints.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.