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Skill Filetypes

Documents
skill-filetypes

Skill Filetypes is an Agent Skill for documents published in the benbrastmckie/nvim repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.

File format conversion routing with specialized sub-agent dispatch

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How to use this skill

Bring this guide into your coding agent with a prompt tailored to the tool you use.

  1. Open your project in Codex.
  2. Copy and paste the prompt below.
  3. Review files and risks before approving any action.
Prompt to paste
Inspect the Agent Skill at https://github.com/benbrastmckie/nvim/blob/HEAD/.opencode/extensions/filetypes/skills/skill-filetypes/SKILL.md and all supporting files. Report provenance, permissions, scripts, dependencies, and security risks. Propose an exact installation into .agents/skills/skill-filetypes, but wait for my approval before writing files or running scripts.

Copying this prompt does not install or run the skill. Review third-party files before use.

Filetypes Skill

Thin wrapper that routes file format operations to the filetypes-router-agent, which then delegates to specialized sub-agents based on file type.

Context Pointers

Reference (do not load eagerly):

  • Path: .opencode/context/core/formats/subagent-return.md
  • Purpose: Return validation
  • Load at: Subagent execution only

Note: This skill is a thin wrapper. Context is loaded by the delegated agents, not this skill.

Trigger Conditions

This skill activates when:

Direct Invocation

  • User explicitly runs /convert command
  • User requests file format conversion in conversation

Implicit Invocation (during task implementation)

When an implementing agent encounters any of these patterns:

Plan step language patterns:

  • "Extract text from [file].pdf"
  • "Extract content from [file]"
  • "Convert [file] to markdown"
  • "Convert [file] to PDF"
  • "Generate PDF from [documentation/file]"
  • "Read content from [file].docx"
  • "Create PDF version of [file]"
  • "Parse [file].pdf for content"
  • "Import [file] content"

File extension detection:

  • Source file has extension: .pdf, .docx, .xlsx, .pptx, .html
  • Target mentions: "markdown", ".md", "PDF", ".pdf"

Task description keywords:

  • "document conversion"
  • "format transformation"
  • "extract from PDF"
  • "generate PDF"

When NOT to trigger

Do not invoke for:

  • Reading source code files (.py, .js, .lean, etc.)
  • Viewing images without extraction
  • Operations that don't involve format conversion
  • Files already in the target format
  • Spreadsheet-specific operations (use skill-spreadsheet)
  • Presentation-specific operations (use skill-presentation)

Execution

1. Input Validation

Validate required inputs:

  • source_path - Must be provided and file must exist
  • output_path - Optional, defaults to source dir with appropriate extension
# Validate source exists
if [ ! -f "$source_path" ]; then
  return error "Source file not found: $source_path"
fi

# Determine output path if not provided
if [ -z "$output_path" ]; then
  source_dir=$(dirname "$source_path")
  source_base=$(basename "$source_path" | sed 's/\.[^.]*$//')
  source_ext="${source_path##*.}"

  # Infer target extension
  case "$source_ext" in
    pdf|docx|xlsx|pptx|html) output_path="${source_dir}/${source_base}.md" ;;
    md) output_path="${source_dir}/${source_base}.pdf" ;;
    *) return error "Cannot infer output format for .$source_ext" ;;
  esac
fi

2. Context Preparation

Prepare delegation context:

{
  "source_path": "/absolute/path/to/source.pdf",
  "output_path": "/absolute/path/to/output.md",
  "metadata": {
    "session_id": "sess_{timestamp}_{random}",
    "delegation_depth": 1,
    "delegation_path": ["orchestrator", "convert", "skill-filetypes"]
  }
}

3. Invoke Router Agent

CRITICAL: You MUST use the Task tool to spawn the router agent.

Required Tool Invocation:

Tool: Task (NOT Skill)
Parameters:
  - subagent_type: "filetypes-router-agent"
  - prompt: [Include source_path, output_path, metadata]
  - description: "Convert {source_path} to {output_path}"

DO NOT use Skill(filetypes-router-agent) - this will FAIL. Agents live in .opencode/agents/ or extension agent directories, not .opencode/skills/. The Skill tool can only invoke skills from .opencode/skills/.

The router will:

  • Detect source and target formats
  • Select appropriate sub-agent (document, spreadsheet, presentation)
  • Delegate to sub-agent for actual conversion
  • Return standardized JSON result

4. Return Validation

Validate return matches subagent-return.md schema:

  • Status is one of: converted, extracted, partial, failed
  • Summary is non-empty and <100 tokens
  • Artifacts array present with output file path
  • Metadata contains session_id, agent_type, delegation info

5. Return Propagation

Return validated result to caller without modification.


Return Format

See .opencode/context/core/formats/subagent-return.md for full specification.

Expected successful return:

{
  "status": "converted",
  "summary": "Successfully converted document.pdf to document.md using markitdown",
  "artifacts": [
    {
      "type": "implementation",
      "path": "/absolute/path/to/document.md",
      "summary": "Converted markdown document"
    }
  ],
  "metadata": {
    "session_id": "sess_...",
    "agent_type": "document-agent",
    "delegation_depth": 2,
    "delegation_path": ["orchestrator", "convert", "skill-filetypes", "filetypes-router-agent", "document-agent"],
    "tool_used": "markitdown"
  },
  "next_steps": "Review converted document"
}

Error Handling

Input Validation Errors

Return immediately with failed status if source file not found.

Unsupported Format

Return failed status with clear message about supported formats.

Router/Subagent Errors

Pass through the router/subagent's error return verbatim.

Tool Not Available

Return failed status with installation instructions.