What
Anthropic can now push prompt overrides for official (first-party) plugins via the tengu_official_plugin_prompt_overrides GrowthBook feature flag. This allows updating plugin instructions server-side without requiring a CLI release.
Details
- Applies only to plugins from Anthropic's marketplace or known official plugin names
- Overridable fields:
server_instructions,server_instructions_by_server,tools,search_hints,param_descriptions,prompts,skills - If the GrowthBook payload fails schema validation, the baked-in plugin text is used and an error is logged
- Per-server instruction overrides via
server_instructions_by_serverlet different MCP servers within the same plugin get different instructions
Evidence
Plugin prompt override (search for "tengu_official_plugin_prompt_overrides")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
One source agreesOne thing we can check says the same as this entry.
The name it cites is new in this build
New in this build: tengu_official_plugin_prompt_overrides