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Get type info / docs at a Swift source position

swiftGetHoverInfo

Returns SourceKit-LSP hover info and declaration fragment at a given position to help identify retain cycles and disambiguate self captures.

Instructions

[mg.code] SourceKit-LSP textDocument/hover at a (line, character) position. Returns the markdown / plaintext hover content plus a best-effort extracted declaration fragment. Use to disambiguate self captures: a class self in a closure can leak; a struct self can't.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "filePath": "<filePath>",
      "line": "<line>",
      "character": "<character>"
    },
    "name": "swiftGetHoverInfo"
  }
}

Input Schema

Name	Required	Description
`filePath`	Yes	Absolute path to a Swift source file.
`line`	Yes	Zero-based line number (LSP convention).
`character`	Yes	Zero-based UTF-16 character offset within the line.
`projectRoot`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.7.0May 3, 2026

TDQS

A3.9/5.0

Behavior3/5

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

With no annotations, the description carries the full burden. It describes the output (markdown/plaintext hover content and declaration fragment) but does not disclose behavioral traits such as read-only nature, error handling, or performance characteristics. The 'best-effort' qualifier adds some transparency but is insufficient.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise: two sentences that immediately convey the technical identity and a practical use case. Every sentence earns its place without fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite lacking an output schema, the description explains what is returned (markdown/plaintext hover content and declaration fragment). It also gives a concrete usage context. However, it could be more detailed about the return structure or potential failure cases, which prevents a perfect score.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description does not add any meaning beyond the input schema. Schema coverage is 75% (projectRoot lacks description), and the description does not clarify that parameter or provide additional context for other parameters. The description adds zero value for parameter understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it performs a SourceKit-LSP textDocument/hover request at a specific position, which is a specific verb+resource. It distinguishes from sibling tools like swiftGetSymbolDefinition by focusing on hover content and type info, not definitions.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides a explicit use case: disambiguating self captures in closures. However, it does not mention when not to use it or suggest alternatives, which prevents a higher score.

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