Retrieve the current Lean 4 tactic proof state at a specified cursor position in a .lean file to inspect goals and hypotheses during proof development.
Queries interactive Lean 4 tactic proof state at cursor position ($/lean/plainGoal)
| Name | Required | Description | Default |
|---|---|---|---|
| col | No | 1-based column number | |
| line | Yes | 1-based line number | |
| filePath | Yes | Absolute or relative path to the .lean file | |
| character | No | Synonym for col |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden. 'Queries' implies a read-only operation and 'interactive proof state' indicates it depends on an active Lean session, which is useful. It does not disclose what the returned goal state looks like or whether the file must be open/saved, leaving some behavior implicit.
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 with no filler. It front-loads the core action and resource, and the embedded LSP method adds precise context without extra length.
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 simple query tool, the description covers the essential purpose and location semantics. However, with no output schema and no annotations, details about the return value and operational prerequisites (e.g., file must be open in a Lean session) are left unspecified.
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 the schema already documents all four parameters. The description adds only the general notion of 'cursor position', which loosely ties filePath, line, and col/character together but does not add meaningful detail beyond the schema.
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 ('Queries') and names a precise resource: 'interactive Lean 4 tactic proof state at cursor position'. It also includes the LSP method identifier ($/lean/plainGoal), which adds precision. It does not explicitly contrast with the sibling lean_term_goal, though 'tactic proof state' implies a distinction.
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 phrase 'at cursor position' conveys that the tool should be used when an agent needs the proof state at a particular location in a Lean file. However, it provides no explicit guidance on when to choose this tool over lean_term_goal or other siblings, and no exclusions are stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.