Devin rules and context cost
Project rules in Devin Desktop load into every agent turn when triggered. always_on rules are the most common hidden input tax — full rule text on every message.
Hub: Tokenminning in Devin. Queries: devin global rules, rule activation modes.
Activation modes
From Memories & Rules :
| Mode | trigger: | Context cost |
|---|---|---|
| Always On | always_on | Full rule every message |
| Model Decision | model_decision | Description always; body on demand |
| Glob | glob | Only when matching files touched |
| Manual | manual | Only when @rule-name mentioned |
Prefer glob or model_decision over always_on.
Global and enterprise rules
Audit these the same way as project rules:
- Global:
~/.codeium/windsurf/memories/global_rules.md - Enterprise system rules injected for all users
- Workspace cap: 12,000 characters; global cap: 6,000 characters
Devin global rules queries usually mean this stack — trim or convert to glob triggers.
AGENTS.md
Use AGENTS.md for directory-scoped instructions instead of pasting style guides into chat.
- One concern per rule file
- Reference linter configs instead of duplicating style in prose
- Do not duplicate content across rules,
AGENTS.md, and auto-memories - Prefer Rules over Memories for team knowledge (memories are local, not version-controlled)
Index bloat
Rules are not the only input source — tune .codeiumignore and Max Workspace Size so retrieval does not attach irrelevant files. See Devin Desktop Ignore .
Related
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