What causes "missing required parameter: %s" in github/github-mcp-server?

Add the missing argument with the exact key name from the tool's inputSchema.

missing required parameter: %s

Error message

missing required parameter: %s

What it means

Thrown by RequiredParam in pkg/github/params.go when a required argument is entirely absent from the tool request. This is the first of three checks in the generic required-parameter extractor: presence, type, non-zero. Most string-typed required params (owner, repo, title, query, ...) go through it.

Source

Thrown at pkg/github/params.go:133

	result := int64(f)
	// Check round-trip to detect precision loss for large int64 values
	if float64(result) != f {
		return 0, fmt.Errorf("numeric value %v is too large to fit in int64", f)
	}
	return result, nil
}

// RequiredParam is a helper function that can be used to fetch a requested parameter from the request.
// It does the following checks:
// 1. Checks if the parameter is present in the request.
// 2. Checks if the parameter is of the expected type.
// 3. Checks if the parameter is not empty, i.e: non-zero value
func RequiredParam[T comparable](args map[string]any, p string) (T, error) {
	var zero T

	// Check if the parameter is present in the request
	if _, ok := args[p]; !ok {
		return zero, fmt.Errorf("missing required parameter: %s", p)
	}

	// Check if the parameter is of the expected type
	val, ok := args[p].(T)
	if !ok {
		return zero, fmt.Errorf("parameter %s is not of type %T", p, zero)
	}

	if val == zero {
		return zero, fmt.Errorf("missing required parameter: %s", p)
	}

	return val, nil
}

// RequiredInt is a helper function that can be used to fetch a requested parameter from the request.
// It does the following checks:
// 1. Checks if the parameter is present in the request.

View on GitHub (pinned to 0ea1f775a7)

Solutions

Add the missing argument with the exact key name from the tool's inputSchema.
Check parameter casing/snake_case — the error text names the exact key the server looked for.
If the call previously worked, diff the server version's tool schemas; a new required field may have been introduced.
Validate arguments against inputSchema client-side before dispatch.

Example fix

// before
arguments = { owner, repo, body: "text" } // create_issue missing title
// after
arguments = { owner, repo, title: "Bug report", body: "text" }

Defensive patterns

Strategy: validation

Validate before calling

function requireArgs(args, schema) {
  for (const [name, prop] of Object.entries(schema.properties || {})) {
    if (schema.required?.includes(name) && (args[name] === undefined)) {
      throw new Error(`missing required parameter: ${name}`);
    }
  }
}

Type guard

function hasAllRequired(args: object, required: string[]): args is Record<string, unknown> {
  return required.every((k) => args[k] !== undefined);
}

Try / catch

On 'missing required parameter: X', read the exact key name from the message, add it with a valid value, and retry; the rest of the payload was accepted structurally.

Prevention

Validate against the tool's inputSchema (from tools/list) before dispatch.
Build arguments from typed interfaces so missing keys fail at compile time in TS.
Watch for snake_case/camelCase mismatches between your code and the schema.

When it happens

Trigger: Calling create_issue without title; get_pull_request without pull_number; any tool call where the arguments object is missing a key marked required in the schema.

Common situations: LLM omitting fields it considers optional; client code with typos in key names (PullNumber vs pull_number); schema drift after server upgrade adding a new required param; empty arguments object sent by mistake.

Related errors

AI-assisted analysis of github/github-mcp-server@0ea1f775a7 (2026-08-15). Data as JSON: /api/errors/e642909e2411aaa8. Report an issue: GitHub.