OpenCode FMT

A unified text optimization plugin for OpenCode that sanitizes emojis and formats markdown tables. Built for high-performance pipelines where minimal latency is a requirement.

Features

• Deterministic Emoji Sanitizer: Removes emojis from AI outputs without altering the surrounding whitespace or layout.
• Isolated Table Aligner: Formats Markdown tables by calculating maximum column widths and applying deterministic padding, ensuring visual correctness.
• Low-Latency Engine: Processes AI output efficiently without a full AST-based parser, maintaining near-linear time processing.
• Concealment-Aware Widths: Intelligently calculates table widths by accounting for markdown markers like bold, italics, bold, or italics which are hidden in many views.
• Flat Configuration: Simple, flat boolean configuration file with nested-object validation.

Quick Start

Add the plugin name to your OpenCode config file plugins section in ~/.config/opencode/config.json:

{
  "plugins": [
    "opencode-fmt"
  ]
}

Plugin Configuration

The plugin automatically initializes a default configuration at ~/.config/opencode/fmt/config.json on its first run if it doesn't already exist.

{
  "stripEmojis": true,
  "alignTables": true,
  "concealmentAware": true,
  "logging": false
}

[!NOTE] All configuration keys are booleans. Top-level arrays and unknown keys in config.json are accepted for forward compatibility, but current core behavior only uses the documented keys below. Nested objects are strictly prohibited.

| Key | Default | Description | | :--- | :--- | :--- | | stripEmojis | true | Removes all emojis from the output. | | alignTables | true | Dynamically aligns Markdown tables for visual consistency. | | concealmentAware | true | Accounts for hidden markdown markers (e.g. **, _) in column widths. | | logging | false | Enables duration and raw/clean output logging to opencode-fmt.log. |

Examples

Emoji Sanitization

The sanitizer removes pictographic and dingbat symbols from the text stream.

Before: Hello [hand-wave], our launch [rocket] was a success [party]!
After: Hello , our launch was a success !

(Note: Surrounding whitespaces are strictly preserved for deterministic layout stability, which may result in double spaces where an emoji was removed).

[!NOTE] If a response contains only emojis (and optional whitespace characters), opencode-fmt will replace it with a redaction placeholder:
[Only emojis received and redacted by opencode-fmt]

Table Alignment

The aligner intelligently pads columns based on the longest cell in each column.

Before:

| Header 1 | H2 |
|---|---|
| Val | Long Value |

After:

| Header 1 | H2         |
| -------- | ---------- |
| Val      | Long Value |

Architectural Constraints

This plugin is governed by strict technical rules to preserve its performance:

1. AST-Free Processing: No heavyweight parsing into an Abstract Syntax Tree.
2. Zero Runtime Dependencies: Built purely on native Bun/Node APIs and the core plugin hook.
3. Flat Config: No nested objects are allowed in config.json to prevent parsing overhead. The configuration is stored in ~/.config/opencode/fmt/config.json. Top-level arrays are permitted for list-based features. Any unknown keys are merged but ignored by core logic.
4. Diff Stability: Non-target text (pure paragraphs) is preserved byte-for-byte in the output.

Inspiration

This plugin was inspired by two community plugins that pioneered single-feature plugin design:

• opencode-md-table-formatter by @franlol — Automatic Markdown table formatting with concealment mode support
• opencode-unmoji by @bastiangx — Strips emojis from agent output

Both showed that focused, lightweight plugins can solve specific pain points elegantly. This plugin follows the same philosophy: one concern, done well.

License

This project is licensed under the MIT License. See the LICENSE file for details.

© 2026 Ritesh Kumar Pal