Speedgrapher plugin
A technical writing assistant for Antigravity: a Markdown side panel, four MCP checks and five skills from notes to publication.
- 52 ★ on the repository
- Last commit
- Apache-2.0
Extended access
Why this level
- The MCP server and checks read Markdown files by absolute path and run Vale.
- A binary built from source is installed into `$GOPATH/bin`.
Install
Manual install
make install-pluginRun in the cloned repository; needs Go 1.26, Node.js 20 and Vale 3. The plugin is then switched on in Antigravity.
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- The MCP server and checks read Markdown files by absolute path and run Vale.
- A binary built from source is installed into `$GOPATH/bin`.
This is third-party code. Review the repository files before installing.
What it does
Speedgrapher joins three parts in one Go and Node.js package. A Markdown side panel has four modes: reader, editor, reviewer and raw. The editor shows Heatmap, Slop, Vale and Fog lenses and applies a suggested fix with one click. Posts and docs get an SEO and GEO audit. The MCP server exposes four checks: `fog` computes Gunning Fog readability, `slop` scores canned phrases and AI clichés on a 0 to 100 scale, `vale` lints style with Google, proselint and write-good rules, and `seo` audits titles, descriptions, structure and `alt` attributes. The same checks run from the shell with `speedgrapher audit` and `speedgrapher call`. Five skills, `speedgrapher`, `ideate`, `draft`, `readability` and `publish`, carry a text from interview and outline to release.
Who it is for. Technical writers and developers who write posts, READMEs and docs in Antigravity and want clarity checks right in the editor.
Good fit when
- A post draft must be cleared of corporate jargon and canned phrases.
- Before publication the title, description and heading order need an SEO check.
- A reviewer leaves comments right in the Markdown and the author resolves them in the panel.
- A docs build in CI should fail when the Fog or Vale score leaves the norm.
Not a fit when
- The work does not run in Antigravity: the panel and the plugin install target it.
- You need literary editing: the checks are tuned for technical prose.
- Go, Node.js and Vale are not installed for the build and style check.
Example request
Open the `article.md` draft in the Speedgrapher panel, run `fog`, `slop` and `vale` and suggest edits for the paragraphs with the highest scores.Limitations
The plugin builds from source: it needs Go 1.26 or newer, Node.js 20 or newer and Vale 3 on `PATH`. `make install-plugin` copies files to `~/.gemini/config/plugins/speedgrapher`, and the plugin is switched on in the Installed tab of Customizations. The `slop` score is tuned on pre-2021 human prose and is a guide rather than proof of authorship. Only the Antigravity path is described, and connecting the `speedgrapher mcp` server to other MCP clients is not covered in the README. Target values: Fog 11 to 15, Slop under 20, Vale with no warnings, SEO 85 or higher.
How to disable. Switch Speedgrapher to Off in the Installed tab of Customizations. Delete the `~/.gemini/config/plugins/speedgrapher` folder and the `speedgrapher` binary in `$GOPATH/bin` by hand.
FAQ
How do I install Speedgrapher?
Clone the repository and run `make install-plugin`. The command builds `bin/speedgrapher`, installs the binary to `$GOPATH/bin` and copies the plugin files to `~/.gemini/config/plugins/speedgrapher`. Then switch the plugin on in Antigravity.
Which checks does the MCP server provide?
Four: `fog` for readability, `slop` for canned phrases and AI clichés, `vale` for style and grammar and `seo` for titles, descriptions and structure. The server starts with `speedgrapher mcp`.
How do I run the checks from the shell?
With `speedgrapher audit` and a JSON argument holding the file path and keyword. For a single check use `speedgrapher call fog`, `call slop`, `call vale` and `call seo`.
What does reviewing in the panel do?
Reviewer mode locks direct editing and shows `<!-- review: ... -->` comments under paragraphs along with the check lenses. Notes can be added, edited and resolved with one click.
What are the five skills for?
`ideate` interviews and outlines with an inverted pyramid, `draft` writes a draft with a 150-word lead, `readability` removes jargon and clichés, `publish` resolves notes and checks SEO tags, and `speedgrapher` opens the panel and routes tasks.
Discussion
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README in short
Speedgrapher is presented as an open source technical writing assistant for Antigravity: a panel, an MCP server and skills in one package. It covers the panel modes, a table of checks with target scores, shell commands, skills and building from source.