Init tech declaration

Init Tech Declaration

Generates or refreshes .opencode/harness/rules/tech.md — the lazy-load router for the project's tech conventions. This file is injected into every session via the config instructions array and survives compaction.

When to Use

• First time adopting this harness on a project
• Adding or removing a tech (e.g. new frontend, dropped service)
• Drift detected ("router says rust, but .py files are being edited")
• Major refactor that restructured directories

Steps

1. Run detect-tech.md (manifest glob + proximity, Steps 1–3) from this skill's directory: Read .opencode/skills/init-tech-declaration/detect-tech.md.
2. Map detected tech to dir names (e.g. Cargo.toml → rust, package.json with react dep → react). JS/TS framework detection is inlined in detect-tech.md; non-JS/TS uses the manifest → tech-dir table inlined there. When a framework is detected inside a language (e.g. FastAPI in Python), record it as a hint: python (fastapi).
3. Write the result to .opencode/harness/rules/tech.md as a lazy-load router — each entry tells the agent which files to Read before writing code in that stack:

   ## Tech
   
   Conventions are loaded lazily — this file is the router, not the content.
   BEFORE writing or modifying code in a stack below, Read the matching files:
   
   - `rust` → `.opencode/harness/tech/rust/*.md` + `.opencode/harness/tech/common/*.md`
   - `python (fastapi)` → `.opencode/harness/tech/python/*.md` + `.opencode/harness/tech/common/*.md`
   - `react` → `.opencode/harness/tech/react/*.md` + `.opencode/harness/tech/common/*.md`
   
   Polyglot: when a task spans multiple stacks, load each stack's conventions and
   apply each to its own code. Do not mix conventions across boundaries.
   
   Other folders under `.opencode/harness/tech/` stay dormant — add them above to
   activate. Run the `init-tech-declaration` skill to detect and declare stacks.
   

4. Ensure the config file wires tech.md into instructions. Check for any of these filenames in the project root (first match wins): opencode.json, opencode.jsonc, .opencode.jsonc. If the config file exists but has no instructions key (or instructions does not include the tech.md path), add .opencode/harness/rules/tech.md to the array — preserve every other key. If no config file exists, create .opencode.jsonc:

   {
     "$schema": "https://opencode.ai/config.json",
     "instructions": [".opencode/harness/rules/tech.md"]
   }
   

5. Opt-in always-load (single-stack only). If the project uses exactly one tech stack, ask the user whether to also load that stack's conventions into every session via instructions globs (trades context budget for guaranteed enforcement). If yes, append the stack's glob:

   "instructions": [
     ".opencode/harness/rules/tech.md",
     ".opencode/harness/tech/rust/*.md",
     ".opencode/harness/tech/common/*.md"
   ]
   

   For polyglot projects, skip this — the lazy router is the right default.
6. Show the user a diff before writing. Do not silently modify files.
7. Report: which tech dirs exist vs missing (missing → falls back to common/); config wiring status; whether always-load was applied.

Output

A .opencode/harness/rules/tech.md router file + an instructions entry in the config. Example router for a Rust + React monorepo:

## Tech

Conventions are loaded lazily — this file is the router, not the content.
BEFORE writing or modifying code in a stack below, Read the matching files:

- `rust` → `.opencode/harness/tech/rust/*.md` + `.opencode/harness/tech/common/*.md`
- `react` → `.opencode/harness/tech/react/*.md` + `.opencode/harness/tech/common/*.md`

Polyglot: when a task spans multiple stacks, load each stack's conventions and
apply each to its own code. Do not mix conventions across boundaries.

Other folders under `.opencode/harness/tech/` stay dormant — add them above to
activate. Run the `init-tech-declaration` skill to detect and declare stacks.

Notes

• Safe to re-run; idempotent.
• If detection finds nothing recognizable, write a router with only common and warn the user.
• The detection machinery (detect-tech.md) is a tool, not a runtime step.
• The /adopt command orchestrates this skill as part of full harness setup; it also scaffolds a project AGENTS.md from AGENTS.template.md in this folder.