fix: constrain speculative domain discovery

[FreeOnePlus]

Summary

• define mutually exclusive scopes for all eight stable top-level domains
• require single-domain-first progressive discovery instead of speculative multi-manifest browsing
• guide unqualified cluster-history requests to preserve every usable recorded series
• document the deterministic Host orchestration rule in English and Simplified Chinese
• update the changelog and regression contracts

Root cause

A Dify 1.16.1 Agent expanded Catalog, Cluster, Pipeline, Query, and Governance manifests for one unqualified cluster-history question. Each later model step carried the accumulated manifests again, increasing context cost and encouraging unrelated probes. The Server contract did not state the domain exclusions or the single-domain-first rule strongly enough.

Contract behavior

• the registered top-level list remains eight stable read-only domains
• no probabilistic Server-side router or dynamic re-registration is introduced
• each domain declares both its owned capability categories and excluded scopes
• the common discovery instruction forbids speculative multi-domain expansion
• unqualified current or historical cluster-operation questions use doris_cluster
• unqualified resource-history calls omit resource, preserving usable series and reporting unavailable series separately
• the final top-level tools/list remains bounded at 22,883 bytes

Real Host validation

Tested through Dify 1.16.1, /mcp/legacy, and a real Doris 4.0.5 environment:

• before: five domain manifests expanded; 100,093 cumulative tokens
• after: only doris_cluster expanded; 33,510 cumulative tokens
• reduction: approximately 66.5%
• Server audit log contained only Cluster-domain discovery and resource-history child calls
• storage history remained readable with zero points; audit-backed query/user series reported permission denial separately

Validation

• focused manifest, Host-exposure, and dispatcher suites: 112 passed
• full suite: 1782 passed, 83 skipped
• mypy doris_mcp_server
• ruff check .
• python generate_tool_catalog.py --check
• git diff --check