docs(openspec): add harden-opencode-runtime-integration spec.md

Author: loong10k

openspec/changes/harden-opencode-runtime-integration/specs/cli-runtime/spec.md

@@ -0,0 +1,60 @@
+# Delta for CLI Runtime
+
+## ADDED Requirements
+
+### Requirement: CLI concurrency limits are enforced
+
+The executor MUST enforce `maxConcurrentExecutions` when the configured value is greater than zero.
+
+#### Scenario: Limit reached
+
+- GIVEN the concurrency limit is N
+- AND N executions are active
+- WHEN another execution is submitted
+- THEN it MUST wait for capacity or fail according to the selected admission policy
+- AND MUST NOT spawn an additional child process before capacity is available
+
+### Requirement: CLI output retention is bounded
+
+The executor MUST bound retained stdout and stderr independently.
+
+#### Scenario: Child output exceeds configured capture limit
+
+- GIVEN a configured output capture limit
+- WHEN a child emits more bytes than the limit
+- THEN retained output MUST remain within the configured bound
+- AND the result MUST indicate truncation
+
+### Requirement: CLI execution supports per-invocation environment isolation
+
+The executor MUST allow a caller to control environment inheritance and provide environment overrides without mutating the JVM process environment.
+
+#### Scenario: Override one variable
+
+- GIVEN parent environment inheritance is enabled
+- AND an execution override defines a variable
+- WHEN the child process starts
+- THEN the child MUST see the override value
+- AND subsequent unrelated executions MUST NOT inherit that override unless configured
+
+### Requirement: Streaming execution delivers data before process exit
+
+The SDK MUST provide an execution mode that exposes stdout and stderr incrementally while the process is running.
+
+#### Scenario: Long running JSON output
+
+- GIVEN an OpenCode process emits multiple JSON event lines over time
+- WHEN the caller uses streaming execution
+- THEN each complete event line MUST be observable before process termination
+- AND process completion MUST be available through a separate completion result
+
+### Requirement: Process outcomes are classified
+
+The SDK MUST distinguish success, non-zero exit, spawn failure, timeout, and cancellation.
+
+#### Scenario: Spawn failure
+
+- GIVEN the configured executable does not exist
+- WHEN execution is attempted
+- THEN the result or completion failure MUST identify spawn failure
+- AND MUST NOT report it as a normal non-zero OpenCode exit