Module: Legion::MCP::TierRouter

Extended by:
Logging::Helper
Defined in:
lib/legion/mcp/tier_router.rb

Constant Summary collapse

CONFIDENCE_TIER0 = 
0.8
CONFIDENCE_TIER1 = 
0.6

Class Method Summary collapse

Class Method Details

.execute_tool_chain(tool_chain, params, request_id: nil) ⇒ Object

rubocop:disable Metrics/MethodLength



145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
 
# File 'lib/legion/mcp/tier_router.rb', line 145

def execute_tool_chain(tool_chain, params, request_id: nil) # rubocop:disable Metrics/MethodLength
  tool_chain.map do |tool_name| # rubocop:disable Metrics/BlockLength
    tool_class = find_tool_class(tool_name)
    raise ArgumentError, "unknown tool: #{tool_name}" unless tool_class

    LoggingSupport.info(
      'tier_router.tool_call.start',
      request_id: request_id,
      tool_name:  tool_name,
      params:     LoggingSupport.summarize_params(params)
    )

    result = if params.empty?
               tool_class.call
             else
               tool_class.call(**params.transform_keys(&:to_sym))
             end

    LoggingSupport.info(
      'tier_router.tool_call.complete',
      request_id: request_id,
      tool_name:  tool_name,
      result:     LoggingSupport.summarize_result(result)
    )

    result
  rescue StandardError => e
    handle_exception(e, level: :warn, operation: 'legion.mcp.tier_router.execute_tool_chain')
    LoggingSupport.warn(
      'tier_router.tool_call.failed',
      request_id: request_id,
      tool_name:  tool_name,
      error:      e.message
    )
    raise
  end
end

.find_tool_class(tool_name) ⇒ Object 



216
217
218
219
220
221
222
 
# File 'lib/legion/mcp/tier_router.rb', line 216

def find_tool_class(tool_name)
  return nil unless defined?(Legion::MCP::Server)

  Legion::MCP::Server.tool_registry.find do |klass|
    klass.respond_to?(:tool_name) && klass.tool_name == tool_name
  end
end

.generate_response(results, pattern) ⇒ Object 



183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
 
# File 'lib/legion/mcp/tier_router.rb', line 183

def generate_response(results, pattern)
  template = pattern[:response_template]

  if template && transformer_available?
    begin
      client = Legion::Extensions::Transformer::Client.new
      rendered = client.transform(transformation: template, payload: { results: results })
      return rendered[:result] if rendered[:success]
    rescue StandardError => e
      handle_exception(e, level: :debug, operation: 'legion.mcp.tier_router.generate_response')
      log.debug("TierRouter#generate_response transformer failed: #{e.message}")
    end
  end

  results.size == 1 ? results.first : results
end

.normalize_intent(intent) ⇒ Object 



141
142
143
 
# File 'lib/legion/mcp/tier_router.rb', line 141

def normalize_intent(intent)
  intent.to_s.strip.downcase.gsub(/\s+/, ' ')
end

.route(intent:, params: {}, context: {}) ⇒ Object

rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity



18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
 
# File 'lib/legion/mcp/tier_router.rb', line 18

def route(intent:, params: {}, context: {}) # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity
  start_time = ::Process.clock_gettime(::Process::CLOCK_MONOTONIC)
  normalized = normalize_intent(intent)
  intent_hash = Digest::SHA256.hexdigest(normalized)
  request_id = LoggingSupport.request_id_from(context, params) || "route_#{intent_hash[0, 8]}"

  LoggingSupport.info(
    'tier_router.start',
    request_id:   request_id,
    intent_hash:  intent_hash[0, 12],
    intent:       LoggingSupport.summarize_text(intent),
    params:       LoggingSupport.summarize_params(params),
    context_keys: context.respond_to?(:keys) ? context.keys.map(&:to_s) : []
  )

  ContextGuard.record_request(intent_hash)

  pattern = PatternStore.lookup(intent_hash, request_id: request_id)
  lookup_source = :exact

  unless pattern
    pattern = try_semantic_lookup(normalized, request_id: request_id)
    lookup_source = pattern ? :semantic : :miss
  end

  LoggingSupport.info(
    'tier_router.lookup',
    request_id: request_id,
    source:     lookup_source,
    confidence: pattern&.dig(:confidence)&.round(3),
    tool_chain: Array(pattern&.dig(:tool_chain))
  )

  unless pattern
    LoggingSupport.info('tier_router.decision', request_id: request_id, tier: 2, reason: 'no matching pattern')
    return tier2_response('no matching pattern')
  end

  confidence = pattern[:confidence] || 0.0

  if confidence < CONFIDENCE_TIER1
    LoggingSupport.info(
      'tier_router.decision',
      request_id: request_id,
      tier:       2,
      reason:     'low confidence',
      confidence: confidence.round(3),
      tool_chain: Array(pattern[:tool_chain])
    )
    return tier2_response('low confidence')
  end

  if confidence < CONFIDENCE_TIER0
    LoggingSupport.info(
      'tier_router.decision',
      request_id: request_id,
      tier:       1,
      reason:     'confidence below tier 0 threshold',
      confidence: confidence.round(3),
      tool_chain: Array(pattern[:tool_chain])
    )
    return tier1_response(pattern, 'confidence below tier 0 threshold')
  end

  guard_result = ContextGuard.check(pattern, params, context)
  LoggingSupport.info(
    'tier_router.guard',
    request_id: request_id,
    passed:     guard_result[:passed],
    reason:     guard_result[:reason]
  )
  unless guard_result[:passed]
    LoggingSupport.info(
      'tier_router.decision',
      request_id: request_id,
      tier:       1,
      reason:     guard_result[:reason],
      confidence: confidence.round(3)
    )
    return tier1_response(pattern, guard_result[:reason])
  end

  begin
    LoggingSupport.info(
      'tier_router.execute',
      request_id: request_id,
      tool_chain: Array(pattern[:tool_chain]),
      params:     LoggingSupport.summarize_params(params)
    )

    results = execute_tool_chain(pattern[:tool_chain], params, request_id: request_id)
    response = generate_response(results, pattern)
    PatternStore.record_hit(intent_hash, request_id: request_id)
    PatternStore.learn_response_template(intent_hash, results.first, request_id: request_id) if results.size == 1

    elapsed_ms = ((::Process.clock_gettime(::Process::CLOCK_MONOTONIC) - start_time) * 1000).round(2)
    LoggingSupport.info(
      'tier_router.complete',
      request_id: request_id,
      tier:       0,
      latency_ms: elapsed_ms,
      confidence: pattern[:confidence]&.round(3),
      response:   LoggingSupport.summarize_result(response)
    )
    {
      tier:               0,
      response:           response,
      latency_ms:         elapsed_ms,
      pattern_confidence: pattern[:confidence]
    }
  rescue StandardError => e
    handle_exception(e, level: :warn, operation: 'legion.mcp.tier_router.route')
    LoggingSupport.warn(
      'tier_router.execute.failed',
      request_id: request_id,
      error:      e.message,
      tool_chain: Array(pattern[:tool_chain])
    )
    PatternStore.record_miss(intent_hash, request_id: request_id)
    tier1_response(pattern, "tool chain failed: #{e.message}")
  end
end

.tier1_response(pattern, reason) ⇒ Object 



228
229
230
 
# File 'lib/legion/mcp/tier_router.rb', line 228

def tier1_response(pattern, reason)
  { tier: 1, response: nil, pattern: pattern, reason: reason }
end

.tier2_response(reason) ⇒ Object 



232
233
234
 
# File 'lib/legion/mcp/tier_router.rb', line 232

def tier2_response(reason)
  { tier: 2, response: nil, reason: reason }
end

.transformer_available? ⇒ Boolean

Returns:

  • (Boolean) 


224
225
226
 
# File 'lib/legion/mcp/tier_router.rb', line 224

def transformer_available?
  defined?(Legion::Extensions::Transformer::Client)
end

.try_semantic_lookup(normalized_intent, request_id: nil) ⇒ Object 



200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
 
# File 'lib/legion/mcp/tier_router.rb', line 200

def try_semantic_lookup(normalized_intent, request_id: nil)
  return nil unless defined?(Legion::MCP::EmbeddingIndex) && Legion::MCP::EmbeddingIndex.populated?

  embedder = Legion::MCP::EmbeddingIndex.instance_variable_get(:@embedder)
  return nil unless embedder

  intent_vector = embedder.call(normalized_intent)
  return nil unless intent_vector

  PatternStore.lookup_semantic(intent_vector, request_id: request_id)
rescue StandardError => e
  handle_exception(e, level: :debug, operation: 'legion.mcp.tier_router.try_semantic_lookup')
  LoggingSupport.debug('tier_router.semantic_lookup.failed', request_id: request_id, error: e.message)
  nil
end