Add ECA (Editor Code Assistant) harness support

[lockie]

Who is submitting this PR?

Field	Value
Your model + version	GLM-5.2 (zai-coding-plan/glm-5.2)
Harness + version	ECA 0.147.3
All plugins installed	superpowers (local checkout), adr, caveman, context-mode
Human partner who reviewed this diff	Andrew Kravchuk (@lockie)

What problem are you trying to solve?

ECA (Editor Code Assistant) is an open-source AI pair programming tool (https://eca.dev) with a plugin system that supports skills, hooks, MCP servers, and agents. Users running ECA had no way to use Superpowers — the plugin system is compatible, but Superpowers lacked the .eca-plugin/ directory structure and hook definitions that ECA needs to discover and load the plugin.

This was experienced firsthand: after configuring Superpowers as a plugin source in ECA's config.json, the skills were not discovered and no bootstrap was injected. The using-superpowers skill content never reached the model, so no skills auto-triggered.

What does this PR change?

Adds ECA as a supported harness using the Shape A (shell-hook) pattern, the same integration shape as Cursor and Copilot CLI:

• .eca-plugin/marketplace.json — marketplace entry for plugin discovery
• .eca-plugin/superpowers/eca.json — plugin manifest pointing to skills
• .eca-plugin/superpowers/hooks/hooks.json — chatStart and postCompact hooks that run the shared hooks/session-start script
• .eca-plugin/superpowers/hooks/session-start — symlink to the shared hooks/session-start
• .eca-plugin/superpowers/skills — symlink to the repo-root skills/
• skills/using-superpowers/references/eca-tools.md — ECA tool mapping
• docs/README.eca.md — install/troubleshooting guide
• tests/eca/ — plugin structure validation tests
• tests/hooks/test-session-start.sh — ECA hook output test case
• .version-bump.json — registered the ECA marketplace version
• scripts/sync-to-codex-plugin.sh — added /.eca-plugin/ to excludes
• README.md, SKILL.md, docs/porting-to-a-new-harness.md — documentation pointers

ECA sets no harness-specific environment variables, so the hooks/session-start script falls into the existing else branch that emits {"additionalContext": "..."} — the SDK standard format that ECA's chatStart hook honors.

The postCompact hook ensures the bootstrap is re-injected after context compaction, matching the behavior of Claude Code's compact matcher.

Is this change appropriate for the core library?

Yes. ECA is a general-purpose coding agent, not a project-specific or domain-specific tool. This adds a new harness integration using the same pattern as existing harnesses (Claude Code, Cursor, Copilot CLI, etc.). Skills, bootstrap injection, and tool mapping are general-purpose — they benefit anyone using ECA regardless of project type.

What alternatives did you consider?

• Submitting to the eca-plugins marketplace repo only: The official eca-plugins repo at github.com/editor-code-assistant/eca-plugins has a plugin entry for superpowers, but it is skills-only (no hooks). Adding hooks there would be a separate process and wouldn't give users the full Superpowers experience (no bootstrap injection). Hosting the plugin from the Superpowers repo itself gives users the complete integration.
• Requiring manual config in user's config.json hooks section: Could work but would require every user to manually configure the hook, which is error-prone and doesn't match the install experience of other harnesses. The .eca-plugin/ directory ships everything through the plugin install mechanism.

Does this PR contain multiple unrelated changes?

No. All changes are part of a single new-harness integration.

Existing PRs

• I have reviewed all open AND closed PRs for duplicates or prior art
• Related PRs: Add ECA (Editor Code Assistant) harness support #1686 (CLOSED)

PR #1686 was a prior attempt at this same integration by the same author. It was closed to start fresh on a clean branch based on the latest dev, incorporating all current contributor guidelines and porting requirements.

Environment tested

Harness	Harness version	Model	Model version/ID
ECA	0.147.3	GLM-4.7	zai-coding-plan/glm-4.7

New harness support

Clean-session transcript for "Let's make a react todo list"

**User:** Let's make a react todo list

**Assistant:** I'll help you create a React todo list! Let me first check the relevant skills to ensure I approach this correctly.

*[eca__skill: Loading skill 'superpowers:using-superpowers']*

*[eca__skill: Loading skill 'superpowers:brainstorming']*

**Assistant:** Using **superpowers:brainstorming** to explore requirements before building.

*[eca__directory_tree: Listing tree: test]*

*[eca__read_file: Reading README.md]*

**Assistant:** I can see you're starting with an empty workspace. Let me ask some questions to understand exactly what you're looking for.

**What's the primary purpose of this todo list?**

A. A simple learning project to understand React basics
B. A functional todo app you'll actually use to track tasks
C. A demonstration/showcase piece to display React skills
D. Something else?

The brainstorming skill auto-triggers before any code is written, confirming the bootstrap injection works.

Evaluation

• Initial prompt: "Let's make a react todo list"
• Eval sessions: 2 (initial plugin setup + debugging hooks.json format, then clean verification session)
• Outcomes: brainstorming skill auto-triggers correctly at session start via chatStart hook. The model loads using-superpowers, then loads brainstorming, announces it, and enters the brainstorming flow (asking clarifying questions) before writing any code.

Rigor

• This change was tested adversarially, not just on the happy path
• I did not modify carefully-tuned content (Red Flags table, rationalizations, "human partner" language) without extensive evals showing the change is an improvement

No skills content was modified. Only infrastructure files were added/changed: plugin directory structure, hook definitions, tool mapping reference, documentation, and tests. The one-line addition to SKILL.md's Platform Adaptation section is a pointer entry (explicitly permitted by the porting guide as the sole allowed SKILL.md edit for a port).

Human review

• A human has reviewed the COMPLETE proposed diff before submission

The complete diff was reviewed by Andrew Kravchuk before submission. The plugin was installed locally and tested in a live ECA session.

🤖 Generated with ECA (zai-coding-plan/glm-5.2)