chore(oas): regenerate OpenAPI artifacts for instructions field + document config

The new top-level config.Config.Instructions field is surfaced in the
OpenAPI spec via GetConfigResponse, so the generated oas/swagger.yaml and
oas/docs.go must be regenerated (make swagger) and committed — this is what
the "Verify OpenAPI Artifacts" CI gate enforces.

Also documents the `instructions` field in docs/configuration.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Dumbris

docs/configuration.md

@@ -649,6 +649,22 @@ All three modes are always available on dedicated endpoints regardless of config
 
 See [Routing Modes](features/routing-modes.md) for complete details.
 
+## Server Instructions
+
+Text returned in the MCP `initialize` response to guide AI agents on how to use the proxy (e.g., use `retrieve_tools` to discover existing tools rather than `search_servers`).
+
+```json
+{
+  "instructions": "Use retrieve_tools to discover tools before assuming a capability is unavailable."
+}
+```
+
+| Field | Type | Default | Description |
+|-------|------|---------|-------------|
+| `instructions` | string | _(built-in)_ | Custom instructions sent in the MCP `initialize` response. When empty, a built-in default explains the `retrieve_tools` → `call_tool_*` workflow and warns against using `search_servers` for existing tools. |
+
+**Note:** Applied at startup / on the next client connect — editing this value does not hot-reload into already-connected MCP sessions.
+
 ---
 
 ## Tool-Level Quarantine

oas/docs.go

@@ -62,6 +62,11 @@ components:
           $ref: '#/components/schemas/secureenv.EnvConfig'
         features:
           $ref: '#/components/schemas/config.FeatureFlags'
+        instructions:
+          description: |-
+            Instructions text returned in the MCP initialize response to guide AI agents.
+            When empty, a built-in default is used that explains retrieve_tools workflow.
+          type: string
         intent_declaration:
           $ref: '#/components/schemas/config.IntentDeclarationConfig'
         listen: