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fix: use transcript model to correct cross-session model contamination #206

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2a1b7b0
fix: use transcript model to correct stale statusline model display
AniAggarwal Mar 7, 2026
889772a
fix: replace non-null assertion with guard to satisfy eslint
AniAggarwal Mar 7, 2026
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20 changes: 20 additions & 0 deletions src/ccstatusline.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,14 @@ import {
} from './utils/speed-window';
import { prefetchUsageDataIfNeeded } from './utils/usage-prefetch';

function formatModelDisplayName(modelId: string): string {
return modelId
.replace(/^claude-/, '')
.replace(/-(\d{8})$/, '')
.replace(/-/g, ' ')
.replace(/\b\w/g, c => c.toUpperCase());
}

function hasSessionDurationInStatusJson(data: StatusJSON): boolean {
const durationMs = data.cost?.total_duration_ms;
return typeof durationMs === 'number' && Number.isFinite(durationMs) && durationMs >= 0;
Expand Down Expand Up @@ -114,6 +122,18 @@ async function renderMultipleLines(data: StatusJSON) {
let tokenMetrics: TokenMetrics | null = null;
if (data.transcript_path) {
tokenMetrics = await getTokenMetrics(data.transcript_path);

if (tokenMetrics.model) {
const stdinModelId = typeof data.model === 'string'
? data.model
: data.model?.id;
if (stdinModelId !== tokenMetrics.model) {
data.model = {
id: tokenMetrics.model,
display_name: formatModelDisplayName(tokenMetrics.model)
};
}
}
}

let sessionDuration: string | null = null;
Expand Down
3 changes: 2 additions & 1 deletion src/types/TokenMetrics.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ export interface TokenUsage {
}

export interface TranscriptLine {
message?: { usage?: TokenUsage };
message?: { usage?: TokenUsage; model?: string };
isSidechain?: boolean;
timestamp?: string;
isApiErrorMessage?: boolean;
Expand All @@ -19,4 +19,5 @@ export interface TokenMetrics {
cachedTokens: number;
totalTokens: number;
contextLength: number;
model: string | null;
}
27 changes: 18 additions & 9 deletions src/utils/__tests__/context-percentage.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 100000
contextLength: 100000,
model: null
}
};

Expand Down Expand Up @@ -61,7 +62,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 42000
contextLength: 42000,
model: null
}
};

Expand All @@ -79,7 +81,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 42000
contextLength: 42000,
model: null
}
};

Expand All @@ -95,7 +98,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 2000000
contextLength: 2000000,
model: null
}
};

Expand All @@ -111,7 +115,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 42000
contextLength: 42000,
model: null
}
};

Expand All @@ -127,7 +132,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 42000
contextLength: 42000,
model: null
}
};

Expand All @@ -148,7 +154,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 42000
contextLength: 42000,
model: null
}
};

Expand All @@ -166,7 +173,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 42000
contextLength: 42000,
model: null
}
};

Expand All @@ -188,7 +196,8 @@ describe('calculateContextPercentage', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 42000
contextLength: 42000,
model: null
}
};

Expand Down
79 changes: 76 additions & 3 deletions src/utils/__tests__/jsonl-metrics.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,7 @@ function makeTranscriptLine(params: {
output?: number;
isSidechain?: boolean;
isApiErrorMessage?: boolean;
model?: string;
}): string {
return JSON.stringify({
timestamp: params.timestamp,
Expand All @@ -57,7 +58,8 @@ function makeTranscriptLine(params: {
usage: {
input_tokens: params.input ?? 0,
output_tokens: params.output ?? 0
}
},
model: params.model
}
: undefined
});
Expand Down Expand Up @@ -155,7 +157,8 @@ describe('jsonl transcript metrics', () => {
outputTokens: 141,
cachedTokens: 92,
totalTokens: 2032,
contextLength: 250
contextLength: 250,
model: null
});
});

Expand All @@ -166,10 +169,80 @@ describe('jsonl transcript metrics', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 0
contextLength: 0,
model: null
});
});

it('returns the model from the most recent assistant entry', async () => {
const root = fs.mkdtempSync(path.join(os.tmpdir(), 'ccstatusline-jsonl-metrics-'));
tempRoots.push(root);
const transcriptPath = path.join(root, 'model.jsonl');
fs.writeFileSync(transcriptPath, [
makeTranscriptLine({
timestamp: '2026-01-01T10:00:00.000Z',
type: 'user'
}),
makeTranscriptLine({
timestamp: '2026-01-01T10:00:05.000Z',
type: 'assistant',
input: 100,
output: 50,
model: 'claude-sonnet-4-5-20250929'
})
].join('\n'));

const metrics = await getTokenMetrics(transcriptPath);
expect(metrics.model).toBe('claude-sonnet-4-5-20250929');
});

it('returns null model when the last entry is a user message (API in progress)', async () => {
const root = fs.mkdtempSync(path.join(os.tmpdir(), 'ccstatusline-jsonl-metrics-'));
tempRoots.push(root);
const transcriptPath = path.join(root, 'model-pending.jsonl');
fs.writeFileSync(transcriptPath, [
makeTranscriptLine({
timestamp: '2026-01-01T10:00:00.000Z',
type: 'user'
}),
makeTranscriptLine({
timestamp: '2026-01-01T10:00:05.000Z',
type: 'assistant',
input: 100,
output: 50,
model: 'claude-sonnet-4-5-20250929'
}),
makeTranscriptLine({
timestamp: '2026-01-01T10:01:00.000Z',
type: 'user'
})
].join('\n'));

const metrics = await getTokenMetrics(transcriptPath);
expect(metrics.model).toBeNull();
});

it('returns null model when transcript has no model field', async () => {
const root = fs.mkdtempSync(path.join(os.tmpdir(), 'ccstatusline-jsonl-metrics-'));
tempRoots.push(root);
const transcriptPath = path.join(root, 'no-model.jsonl');
fs.writeFileSync(transcriptPath, [
makeTranscriptLine({
timestamp: '2026-01-01T10:00:00.000Z',
type: 'user'
}),
makeTranscriptLine({
timestamp: '2026-01-01T10:00:05.000Z',
type: 'assistant',
input: 100,
output: 50
})
].join('\n'));

const metrics = await getTokenMetrics(transcriptPath);
expect(metrics.model).toBeNull();
});

it('calculates speed metrics from user-to-assistant processing windows', async () => {
const root = fs.mkdtempSync(path.join(os.tmpdir(), 'ccstatusline-jsonl-speed-'));
tempRoots.push(root);
Expand Down
28 changes: 25 additions & 3 deletions src/utils/jsonl-metrics.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -152,7 +152,7 @@ export async function getTokenMetrics(transcriptPath: string): Promise<TokenMetr
try {
// Use Node.js-compatible file reading
if (!fs.existsSync(transcriptPath)) {
return { inputTokens: 0, outputTokens: 0, cachedTokens: 0, totalTokens: 0, contextLength: 0 };
return { inputTokens: 0, outputTokens: 0, cachedTokens: 0, totalTokens: 0, contextLength: 0, model: null };
}

const lines = await readJsonlLines(transcriptPath);
Expand Down Expand Up @@ -194,11 +194,33 @@ export async function getTokenMetrics(transcriptPath: string): Promise<TokenMetr
+ (usage.cache_creation_input_tokens ?? 0);
}

// Check if last entry is a user message (API call may be in progress).
// In that case, don't report the model — it may be stale if the user
// just changed models. After the response, the transcript catches up.
let model: string | null = null;
if (mostRecentMainChainEntry?.message?.model) {
let lastEntryIsUser = false;
for (let i = lines.length - 1; i >= 0; i--) {
const line = lines[i];
if (!line) {
continue;
}
const last = parseJsonlLine(line) as TranscriptLine | null;
if (last?.type === 'assistant' || last?.type === 'user') {
lastEntryIsUser = last.type === 'user';
break;
}
}
if (!lastEntryIsUser) {
model = mostRecentMainChainEntry.message.model;
}
}

const totalTokens = inputTokens + outputTokens + cachedTokens;

return { inputTokens, outputTokens, cachedTokens, totalTokens, contextLength };
return { inputTokens, outputTokens, cachedTokens, totalTokens, contextLength, model };
} catch {
return { inputTokens: 0, outputTokens: 0, cachedTokens: 0, totalTokens: 0, contextLength: 0 };
return { inputTokens: 0, outputTokens: 0, cachedTokens: 0, totalTokens: 0, contextLength: 0, model: null };
}
}

Expand Down
9 changes: 6 additions & 3 deletions src/widgets/__tests__/ContextBar.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,8 @@ describe('ContextBarWidget', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 50000
contextLength: 50000,
model: null
}
};
const widget = new ContextBarWidget();
Expand All @@ -65,7 +66,8 @@ describe('ContextBarWidget', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 50000
contextLength: 50000,
model: null
}
};
const widget = new ContextBarWidget();
Expand All @@ -81,7 +83,8 @@ describe('ContextBarWidget', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 50000
contextLength: 50000,
model: null
}
};
const widget = new ContextBarWidget();
Expand Down
6 changes: 4 additions & 2 deletions src/widgets/__tests__/ContextPercentage.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,8 @@ function render(modelId: string | undefined, contextLength: number, rawValue = f
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength
contextLength,
model: null
}
};
const item: WidgetItem = {
Expand Down Expand Up @@ -72,7 +73,8 @@ describe('ContextPercentageWidget', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 100000
contextLength: 100000,
model: null
}
};

Expand Down
9 changes: 6 additions & 3 deletions src/widgets/__tests__/ContextPercentageUsable.test.ts
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Expand Up @@ -20,7 +20,8 @@ function render(modelId: string | undefined, contextLength: number, rawValue = f
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength
contextLength,
model: null
}
};
const item: WidgetItem = {
Expand Down Expand Up @@ -76,7 +77,8 @@ describe('ContextPercentageUsableWidget', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 200000
contextLength: 200000,
model: null
}
};

Expand All @@ -99,7 +101,8 @@ describe('ContextPercentageUsableWidget', () => {
outputTokens: 0,
cachedTokens: 0,
totalTokens: 0,
contextLength: 42000
contextLength: 42000,
model: null
}
};

Expand Down
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