| name | modify-feature |
| description | TRIGGER when user asks to change the signature, route, method, arguments, or return type of an existing endpoint, config, metric, or ticker. |
CRITICAL: Read and analyze this microservice before starting. Do NOT explore or analyze other microservices. The instructions in this skill are self-contained to this microservice.
CRITICAL: A feature is declared in myserviceapi/definition.go (its define.* var, plus In/Out structs for endpoints) and implemented in service.go (its handler). Edit those, then run cmd/genservice.
CRITICAL: Keep the // MARKER: MyFunction comments when editing.
Workflow
Copy this checklist and track your progress:
Modifying a feature of a microservice:
- [ ] Step 1: Read local CLAUDE.md file
- [ ] Step 2: Identify the feature
- [ ] Step 3: Consult the corresponding "add" skill
- [ ] Step 4: Apply the change
- [ ] Step 5: Generate the boilerplate
- [ ] Step 6: Update the tests
- [ ] Step 7: Housekeeping
Step 1: Read Local CLAUDE.md File
Read the local CLAUDE.md file in the microservice's directory. It contains microservice-specific instructions that should take precedence over global instructions.
Step 2: Identify the Feature
Find the feature's define.* var in myserviceapi/definition.go. Its type determines which "add" skill governs its shape:
define.* kind | Feature type | Corresponding skill |
|---|
define.Function | Functional endpoint | add-function |
define.Web | Web handler | add-web |
define.Config | Configuration property | add-config |
define.Ticker | Ticker | add-ticker |
define.Metric | Metric | add-metric |
define.OutboundEvent | Outbound event | add-outbound-event |
define.InboundEvent | Inbound event | add-inbound-event |
define.Task | Task endpoint | add-task |
define.Workflow | Workflow graph | add-workflow |
Step 3: Consult the Corresponding "Add" Skill
Read the SKILL.md of the corresponding "add" skill identified in the previous step. It defines what the define.* var, the In/Out structs, and the handler should look like. Use it as your reference throughout.
Step 4: Apply the Change
Edit definition.go and/or service.go according to the kind of change. The generated files are NOT touched here.
- Implementation only - edit the handler body in
service.go.
- Property change (route, method, required claims, time budget, load balancing, config default/validation/secret/callback, metric buckets/labels, ticker interval) - edit the corresponding field on the
define.* var in definition.go. Add or remove the field's import if its type requires one (e.g. "time").
- Signature change (arguments added, removed, renamed, or retyped) - edit the In/Out structs in
definition.go (add/remove fields and their jsonschema tags), add or remove sibling complex-type files in the api package as needed, and update the handler signature in service.go.
- Rename - rename the
define.* var, its In/Out structs, and their // MARKER comments in definition.go; rename the handler and its // MARKER in service.go. The generated files pick up the new name on regeneration.
These scopes can overlap; handle a rename-plus-signature change in a single pass.
Step 5: Generate the Boilerplate
From the microservice's directory, run the generator. It regenerates client.go, intermediate.go, mock.go, mock_test.go, and manifest.yaml from the updated definition.go.
go run github.com/microbus-io/fabric/cmd/genservice .
Then verify the microservice compiles with go vet ./... from the project root.
Step 6: Update the Tests
Update service_test.go to match the change: edit test cases that call the feature with the old signature, behavior, or name, and rename the test function (e.g. TestMyService_MyFunction becomes TestMyService_NewName) on a rename.
Step 7: Housekeeping
Follow the housekeeping skill.
