Add Gemini CLI provider for session tracking (#168)

Parse ~/.gemini/tmp/<project>/chats/session-*.json files from Gemini
CLI 0.38+. Uses real token counts (input, output, cached, thoughts)
embedded in each message instead of character estimation. Correctly
separates cached tokens from fresh input to avoid double-charging.

- Pricing for gemini-3.1-pro-preview, gemini-3-flash-preview,
  gemini-2.5-pro, gemini-2.5-flash from official Google API rates
- Tool name normalization (ReadFile->Read, SearchText->Grep, etc.)
- Menubar tab with Google Blue color (#4485F4)

Closes #166

mac/Sources/CodeBurnMenubar/AppStore.swift

@@ -226,6 +226,7 @@ enum ProviderFilter: String, CaseIterable, Identifiable {
     case codex = "Codex"
     case cursor = "Cursor"
     case copilot = "Copilot"
+    case gemini = "Gemini"
     case kiro = "Kiro"
     case opencode = "OpenCode"
     case pi = "Pi"
@@ -247,6 +248,7 @@ enum ProviderFilter: String, CaseIterable, Identifiable {
         case .codex: "codex"
         case .cursor: "cursor"
         case .copilot: "copilot"
+        case .gemini: "gemini"
         case .kiro: "kiro"
         case .opencode: "opencode"
         case .pi: "pi"

mac/Sources/CodeBurnMenubar/Views/AgentTabStrip.swift

@@ -92,6 +92,7 @@ extension ProviderFilter {
         case .codex: return Theme.categoricalCodex
         case .cursor: return Theme.categoricalCursor
         case .copilot: return Color(red: 0x6D/255.0, green: 0x8F/255.0, blue: 0xA6/255.0)
+        case .gemini: return Color(red: 0x44/255.0, green: 0x85/255.0, blue: 0xF4/255.0)
         case .kiro: return Color(red: 0x4A/255.0, green: 0x9E/255.0, blue: 0xC4/255.0)
         case .opencode: return Color(red: 0x5B/255.0, green: 0x83/255.0, blue: 0x5B/255.0)
         case .pi: return Color(red: 0xB2/255.0, green: 0x6B/255.0, blue: 0x3D/255.0)

src/models.ts

@@ -38,7 +38,10 @@ const FALLBACK_PRICING: Record<string, ModelCosts> = {
   'claude-3-5-haiku': { inputCostPerToken: 0.8e-6, outputCostPerToken: 4e-6, cacheWriteCostPerToken: 1e-6, cacheReadCostPerToken: 0.08e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
   'gpt-4o': { inputCostPerToken: 2.5e-6, outputCostPerToken: 10e-6, cacheWriteCostPerToken: 2.5e-6, cacheReadCostPerToken: 1.25e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
   'gpt-4o-mini': { inputCostPerToken: 0.15e-6, outputCostPerToken: 0.6e-6, cacheWriteCostPerToken: 0.15e-6, cacheReadCostPerToken: 0.075e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
-  'gemini-2.5-pro': { inputCostPerToken: 1.25e-6, outputCostPerToken: 10e-6, cacheWriteCostPerToken: 1.25e-6, cacheReadCostPerToken: 0.315e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
+  'gemini-3.1-pro-preview': { inputCostPerToken: 2e-6, outputCostPerToken: 12e-6, cacheWriteCostPerToken: 2e-6, cacheReadCostPerToken: 0.5e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
+  'gemini-3-flash-preview': { inputCostPerToken: 0.5e-6, outputCostPerToken: 3e-6, cacheWriteCostPerToken: 0.5e-6, cacheReadCostPerToken: 0.125e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
+  'gemini-2.5-pro': { inputCostPerToken: 1.25e-6, outputCostPerToken: 10e-6, cacheWriteCostPerToken: 1.25e-6, cacheReadCostPerToken: 0.3125e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
+  'gemini-2.5-flash': { inputCostPerToken: 0.3e-6, outputCostPerToken: 2.5e-6, cacheWriteCostPerToken: 0.3e-6, cacheReadCostPerToken: 0.075e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
   'gpt-5.3-codex': { inputCostPerToken: 2.5e-6, outputCostPerToken: 10e-6, cacheWriteCostPerToken: 2.5e-6, cacheReadCostPerToken: 1.25e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
   'gpt-5.4': { inputCostPerToken: 2.5e-6, outputCostPerToken: 10e-6, cacheWriteCostPerToken: 2.5e-6, cacheReadCostPerToken: 1.25e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
   'gpt-5.4-mini': { inputCostPerToken: 0.4e-6, outputCostPerToken: 1.6e-6, cacheWriteCostPerToken: 0.4e-6, cacheReadCostPerToken: 0.2e-6, webSearchCostPerRequest: WEB_SEARCH_COST, fastMultiplier: 1 },
@@ -241,7 +244,10 @@ export function getShortModelName(model: string): string {
     'gpt-5.2': 'GPT-5.2',
     'gpt-5-mini': 'GPT-5 Mini',
     'gpt-5': 'GPT-5',
+    'gemini-3.1-pro-preview': 'Gemini 3.1 Pro',
+    'gemini-3-flash-preview': 'Gemini 3 Flash',
     'gemini-2.5-pro': 'Gemini 2.5 Pro',
+    'gemini-2.5-flash': 'Gemini 2.5 Flash',
     'o4-mini': 'o4-mini',
     'o3': 'o3',
     'MiniMax-M2.7-highspeed': 'MiniMax M2.7 Highspeed',

src/providers/gemini.ts

@@ -0,0 +1,242 @@
+import { readdir, readFile, stat } from 'fs/promises'
+import { join } from 'path'
+import { homedir } from 'os'
+
+import { calculateCost } from '../models.js'
+import type { Provider, SessionSource, SessionParser, ParsedProviderCall } from './types.js'
+
+const toolNameMap: Record<string, string> = {
+  read_file: 'Read',
+  write_file: 'Write',
+  edit_file: 'Edit',
+  create_file: 'Write',
+  delete_file: 'Delete',
+  list_dir: 'LS',
+  grep_search: 'Grep',
+  search_files: 'Grep',
+  find_files: 'Glob',
+  run_command: 'Bash',
+  web_search: 'WebSearch',
+  ReadFile: 'Read',
+  WriteFile: 'Write',
+  EditFile: 'Edit',
+  ListDir: 'LS',
+  SearchText: 'Grep',
+  Shell: 'Bash',
+}
+
+type GeminiTokens = {
+  input?: number
+  output?: number
+  cached?: number
+  thoughts?: number
+  tool?: number
+  total?: number
+}
+
+type GeminiToolCall = {
+  id: string
+  name: string
+  args: Record<string, unknown>
+  status?: string
+  displayName?: string
+}
+
+type GeminiMessage = {
+  id: string
+  timestamp: string
+  type: 'user' | 'gemini' | 'info'
+  content: string | Array<{ text: string }>
+  tokens?: GeminiTokens
+  model?: string
+  toolCalls?: GeminiToolCall[]
+  thoughts?: unknown[]
+}
+
+type GeminiSession = {
+  sessionId: string
+  projectHash?: string
+  startTime: string
+  lastUpdated?: string
+  messages: GeminiMessage[]
+  kind?: string
+}
+
+function parseSession(data: GeminiSession, seenKeys: Set<string>): ParsedProviderCall[] {
+  const results: ParsedProviderCall[] = []
+
+  const geminiMessages = data.messages.filter(m => m.type === 'gemini' && m.tokens && m.model)
+  if (geminiMessages.length === 0) return results
+
+  const dedupKey = `gemini:${data.sessionId}`
+  if (seenKeys.has(dedupKey)) return results
+  seenKeys.add(dedupKey)
+
+  let totalInput = 0
+  let totalOutput = 0
+  let totalCached = 0
+  let totalThoughts = 0
+  const allTools: string[] = []
+  const bashCommands: string[] = []
+  let model = ''
+
+  for (const msg of geminiMessages) {
+    const t = msg.tokens!
+    totalInput += t.input ?? 0
+    totalOutput += (t.output ?? 0) + (t.thoughts ?? 0)
+    totalCached += t.cached ?? 0
+    totalThoughts += t.thoughts ?? 0
+    if (msg.model && !model) model = msg.model
+
+    if (msg.toolCalls) {
+      for (const tc of msg.toolCalls) {
+        const mapped = toolNameMap[tc.displayName ?? ''] ?? toolNameMap[tc.name] ?? tc.displayName ?? tc.name
+        allTools.push(mapped)
+        if (mapped === 'Bash' && tc.args && typeof tc.args.command === 'string') {
+          const cmd = tc.args.command.split(/\s+/)[0] ?? ''
+          if (cmd) bashCommands.push(cmd)
+        }
+      }
+    }
+  }
+
+  if (totalInput === 0 && totalOutput === 0) return results
+
+  // Gemini's `input` count includes `cached` tokens as a subset, so fresh input
+  // must subtract cached to avoid double-charging at both rates.
+  const freshInput = totalInput - totalCached
+
+  let userMessage = ''
+  const firstUser = data.messages.find(m => m.type === 'user')
+  if (firstUser) {
+    if (Array.isArray(firstUser.content)) {
+      userMessage = firstUser.content.map(c => c.text).join(' ').slice(0, 500)
+    } else if (typeof firstUser.content === 'string') {
+      userMessage = firstUser.content.slice(0, 500)
+    }
+  }
+
+  const tsDate = new Date(data.startTime)
+  if (isNaN(tsDate.getTime()) || tsDate.getTime() < 1_000_000_000_000) return results
+
+  const costUSD = calculateCost(model, freshInput, totalOutput, 0, totalCached, 0)
+
+  results.push({
+    provider: 'gemini',
+    model,
+    inputTokens: freshInput,
+    outputTokens: totalOutput,
+    cacheCreationInputTokens: 0,
+    cacheReadInputTokens: totalCached,
+    cachedInputTokens: totalCached,
+    reasoningTokens: totalThoughts,
+    webSearchRequests: 0,
+    costUSD,
+    tools: [...new Set(allTools)],
+    bashCommands: [...new Set(bashCommands)],
+    timestamp: tsDate.toISOString(),
+    speed: 'standard',
+    deduplicationKey: dedupKey,
+    userMessage,
+    sessionId: data.sessionId,
+  })
+
+  return results
+}
+
+function createParser(source: SessionSource, seenKeys: Set<string>): SessionParser {
+  return {
+    async *parse(): AsyncGenerator<ParsedProviderCall> {
+      let raw: string
+      try {
+        raw = await readFile(source.path, 'utf-8')
+      } catch {
+        return
+      }
+
+      let data: GeminiSession
+      try {
+        data = JSON.parse(raw)
+      } catch {
+        return
+      }
+
+      if (!data.messages || !data.sessionId) return
+
+      const calls = parseSession(data, seenKeys)
+      for (const call of calls) {
+        yield call
+      }
+    },
+  }
+}
+
+function getGeminiTmpDir(): string {
+  return join(homedir(), '.gemini', 'tmp')
+}
+
+async function discoverSessions(): Promise<SessionSource[]> {
+  const sources: SessionSource[] = []
+  const tmpDir = getGeminiTmpDir()
+
+  let projectDirs: string[]
+  try {
+    const entries = await readdir(tmpDir, { withFileTypes: true })
+    projectDirs = entries.filter(e => e.isDirectory()).map(e => e.name)
+  } catch {
+    return sources
+  }
+
+  for (const project of projectDirs) {
+    const chatsDir = join(tmpDir, project, 'chats')
+    let files: string[]
+    try {
+      const entries = await readdir(chatsDir)
+      files = entries.filter(f => f.startsWith('session-') && (f.endsWith('.json') || f.endsWith('.jsonl')))
+    } catch {
+      continue
+    }
+
+    for (const file of files) {
+      const filePath = join(chatsDir, file)
+      const s = await stat(filePath).catch(() => null)
+      if (!s?.isFile()) continue
+      sources.push({ path: filePath, project, provider: 'gemini' })
+    }
+  }
+
+  return sources
+}
+
+export function createGeminiProvider(): Provider {
+  return {
+    name: 'gemini',
+    displayName: 'Gemini',
+
+    modelDisplayName(model: string): string {
+      if (model === 'gemini-auto') return 'Gemini (auto)'
+      const display: Record<string, string> = {
+        'gemini-3-flash-preview': 'Gemini 3 Flash',
+        'gemini-3.1-pro-preview': 'Gemini 3.1 Pro',
+        'gemini-2.5-pro': 'Gemini 2.5 Pro',
+        'gemini-2.5-flash': 'Gemini 2.5 Flash',
+        'gemini-2.0-flash': 'Gemini 2.0 Flash',
+      }
+      return display[model] ?? model
+    },
+
+    toolDisplayName(rawTool: string): string {
+      return toolNameMap[rawTool] ?? rawTool
+    },
+
+    async discoverSessions(): Promise<SessionSource[]> {
+      return discoverSessions()
+    },
+
+    createSessionParser(source: SessionSource, seenKeys: Set<string>): SessionParser {
+      return createParser(source, seenKeys)
+    },
+  }
+}
+
+export const gemini = createGeminiProvider()

src/providers/index.ts

@@ -1,6 +1,7 @@
 import { claude } from './claude.js'
 import { codex } from './codex.js'
 import { copilot } from './copilot.js'
+import { gemini } from './gemini.js'
 import { kiro } from './kiro.js'
 import { pi, omp } from './pi.js'
 import type { Provider, SessionSource } from './types.js'
@@ -50,7 +51,7 @@ async function loadCursorAgent(): Promise<Provider | null> {
   }
 }
 
-const coreProviders: Provider[] = [claude, codex, copilot, kiro, pi, omp]
+const coreProviders: Provider[] = [claude, codex, copilot, gemini, kiro, pi, omp]
 
 export async function getAllProviders(): Promise<Provider[]> {
   const [cursor, opencode, cursorAgent] = await Promise.all([loadCursor(), loadOpenCode(), loadCursorAgent()])

tests/provider-registry.test.ts

@@ -3,7 +3,7 @@ import { providers, getAllProviders } from '../src/providers/index.js'
 
 describe('provider registry', () => {
   it('has core providers registered synchronously', () => {
-    expect(providers.map(p => p.name)).toEqual(['claude', 'codex', 'copilot', 'kiro', 'pi', 'omp'])
+    expect(providers.map(p => p.name)).toEqual(['claude', 'codex', 'copilot', 'gemini', 'kiro', 'pi', 'omp'])
   })
 
   it('includes sqlite providers after async load', async () => {