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Fix MCP CLI bridge numeric arg coercion for schema-less tools #28005

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Merged
pelikhan merged 4 commits into from
Apr 23, 2026
+52 −3
Merged

Fix MCP CLI bridge numeric arg coercion for schema-less tools #28005

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9233b3b
Initial plan
Copilot Apr 23, 2026
8fb4c2d
Fix schema-less numeric coercion in MCP CLI bridge args
Copilot Apr 23, 2026
27d4879
Adjust numeric fallback to parseInt/parseFloat with NaN checks
Copilot Apr 23, 2026
a29c5c2
Refine numeric fallback regex to support exponent-only floats
Copilot Apr 23, 2026
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28 changes: 25 additions & 3 deletions actions/setup/js/mcp_cli_bridge.cjs
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Original file line number Diff line number Diff line change
Expand Up @@ -445,6 +445,7 @@ function parseToolArgs(args, schemaProperties = {}) {
/** @type {Record<string, unknown>} */
const result = {};
let jsonOutput = false;
const hasSchemaProperties = Object.keys(schemaProperties).length > 0;
const { normalizedSchemaKeyMap, ambiguousNormalizedSchemaKeys } = buildNormalizedSchemaKeyMap(schemaProperties);

for (let i = 0; i < args.length; i++) {
Expand All @@ -458,13 +459,13 @@ function parseToolArgs(args, schemaProperties = {}) {
jsonOutput = true;
} else {
const canonicalKey = resolveSchemaPropertyKey(key, schemaProperties, normalizedSchemaKeyMap, ambiguousNormalizedSchemaKeys);
result[canonicalKey] = coerceToolArgValue(canonicalKey, raw.slice(eqIdx + 1), schemaProperties[canonicalKey], result[canonicalKey]);
result[canonicalKey] = coerceToolArgValue(canonicalKey, raw.slice(eqIdx + 1), schemaProperties[canonicalKey], result[canonicalKey], !hasSchemaProperties);
}
} else if (raw === "json") {
jsonOutput = true;
} else if (i + 1 < args.length && !args[i + 1].startsWith("--")) {
const canonicalKey = resolveSchemaPropertyKey(raw, schemaProperties, normalizedSchemaKeyMap, ambiguousNormalizedSchemaKeys);
result[canonicalKey] = coerceToolArgValue(canonicalKey, args[i + 1], schemaProperties[canonicalKey], result[canonicalKey]);
result[canonicalKey] = coerceToolArgValue(canonicalKey, args[i + 1], schemaProperties[canonicalKey], result[canonicalKey], !hasSchemaProperties);
i++;
} else {
const canonicalKey = resolveSchemaPropertyKey(raw, schemaProperties, normalizedSchemaKeyMap, ambiguousNormalizedSchemaKeys);
Expand Down Expand Up @@ -549,9 +550,10 @@ function resolveSchemaPropertyKey(key, schemaProperties, normalizedSchemaKeyMap,
* @param {string} rawValue - Raw CLI value
* @param {{type?: string|string[]}|undefined} schemaProperty - JSON schema property
* @param {unknown} existingValue - Existing value (for repeated flags)
* @param {boolean} [allowNumericFallback=false] - Allow numeric parsing when schema is unavailable
* @returns {unknown}
*/
function coerceToolArgValue(key, rawValue, schemaProperty, existingValue) {
function coerceToolArgValue(key, rawValue, schemaProperty, existingValue, allowNumericFallback = false) {
/** @type {string[]} */
const types = [];
if (schemaProperty && typeof schemaProperty === "object" && "type" in schemaProperty && schemaProperty.type != null) {
Expand Down Expand Up @@ -620,6 +622,26 @@ function coerceToolArgValue(key, rawValue, schemaProperty, existingValue) {
}
}

// When schema metadata is unavailable (e.g. empty tools cache), apply
// conservative numeric coercion fallback for CLI ergonomics.
if (allowNumericFallback && types.length === 0) {
const trimmedValue = rawValue.trim();

if (/^-?\d+$/.test(trimmedValue)) {
const parsedInt = Number.parseInt(trimmedValue, 10);
if (!Number.isNaN(parsedInt) && Number.isSafeInteger(parsedInt)) {
return parsedInt;
}
}

if (/^-?(?:(?:\d+\.\d*|\.\d+)(?:[eE][+-]?\d+)?|\d+[eE][+-]?\d+)$/.test(trimmedValue)) {
const parsedFloat = Number.parseFloat(trimmedValue);
if (!Number.isNaN(parsedFloat) && Number.isFinite(parsedFloat)) {
return parsedFloat;
}
}
Comment on lines +625 to +642
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Copilot AI Apr 23, 2026

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The schema-less numeric fallback coerces floats only when the value matches the decimal-point regex, so scientific notation like 1e3 / -2E-4 (which Number()/parseFloat() parse fine) will not be coerced and will still be sent as a string in schema-less mode. Consider extending the float pattern to allow exponent-only forms (e.g. ^-?\d+(?:\.\d+)?(?:[eE][+-]?\d+)?$) or using a single numeric-validation regex shared by both integer/float branches.

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}

return rawValue;
}

Expand Down
27 changes: 27 additions & 0 deletions actions/setup/js/mcp_cli_bridge.test.cjs
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Original file line number Diff line number Diff line change
Expand Up @@ -145,6 +145,33 @@ describe("mcp_cli_bridge.cjs", () => {
});
});

it("falls back to numeric coercion when schema properties are unavailable", () => {
const { args } = parseToolArgs(["--count", "3", "--max_tokens", "3000"], {});

expect(args).toEqual({
count: 3,
max_tokens: 3000,
});
});

it("coerces scientific notation when schema properties are unavailable", () => {
const { args } = parseToolArgs(["--max_tokens", "1e3", "--threshold", "-2E-4"], {});

expect(args).toEqual({
max_tokens: 1000,
threshold: -0.0002,
});
});

it("preserves non-numeric values when schema properties are unavailable", () => {
const { args } = parseToolArgs(["--start_date", "-1d", "--workflow_name", "daily-issues-report"], {});

expect(args).toEqual({
start_date: "-1d",
workflow_name: "daily-issues-report",
});
});

it("treats MCP result envelopes with isError=true as errors", () => {
formatResponse(
{
Expand Down