Add custom fields to GitHub projects to organize tasks with specific data types like text, numbers, dates, or selections.
Create a custom field for a GitHub project
| Name | Required | Description | Default |
|---|---|---|---|
| projectId | Yes | ||
| name | Yes | ||
| type | Yes | ||
| options | No | ||
| description | No | ||
| required | No |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries full burden for behavioral disclosure. It states 'Create' which implies a write/mutation operation, but doesn't disclose permission requirements, rate limits, whether the operation is idempotent, what happens on failure, or the response format. This is a significant gap for a mutation tool with zero annotation coverage.
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, clear sentence with zero wasted words. It's appropriately sized for a basic tool definition and front-loads the essential information (create custom field). Every word 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 mutation tool with 6 parameters, 0% schema coverage, no annotations, and no output schema, the description is inadequate. It doesn't explain what the tool returns, error conditions, or behavioral aspects. The description should provide more context about the creation operation, parameter meanings, and expected outcomes.
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?
With 0% schema description coverage for 6 parameters, the description provides no parameter information beyond what's inferred from the tool name. It doesn't explain what 'projectId', 'name', 'type', 'options', 'description', or 'required' mean, their formats, constraints, or relationships. The description fails to compensate for the complete lack of schema documentation.
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 clearly states the action ('Create') and resource ('a custom field for a GitHub project'), making the purpose immediately understandable. It distinguishes from siblings like 'update_project_field' by specifying creation rather than modification, though it doesn't explicitly contrast with 'list_project_fields' or other field-related 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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an existing project), when not to use it (e.g., for updating existing fields), or direct alternatives like 'update_project_field' for modifications or 'list_project_fields' for viewing existing fields.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.