Canvas Bulk Grading
Grade Canvas LMS assignments efficiently using rubric-based workflows. This skill requires the Canvas MCP server to be running and authenticated with an instructor or TA token.
Prerequisites
- Canvas MCP server running and connected
- Authenticated with an educator (instructor/TA) Canvas API token
- Assignment must exist and have submissions to grade
- Rubric must already be created in Canvas and associated with the assignment (Canvas API cannot reliably create rubrics -- use the Canvas web UI for that)
Workflow
Step 1: Gather Assignment and Rubric Information
Before grading, retrieve the assignment details and its rubric criteria.
get_assignment_details(course_identifier, assignment_id)
Then get the rubric. Use get_assignment_rubric_details if the rubric is already linked to the assignment, or list_all_rubrics to browse all rubrics in the course:
get_assignment_rubric_details(course_identifier, assignment_id)
list_all_rubrics(course_identifier)
get_rubric_details(course_identifier, rubric_id)
Record the criterion IDs (often prefixed with underscore, e.g., _8027) and rating IDs from the rubric response. These are required for rubric-based grading.
Step 2: List Submissions
Retrieve all student submissions to determine how many need grading:
list_submissions(course_identifier, assignment_id)
Note the user_id for each submission and the workflow_state (submitted, graded, pending_review). Count the submissions that need grading to determine which strategy to use.
Step 3: Choose a Grading Strategy
Use this decision tree based on the number of submissions to grade:
How many submissions need grading?
|
+-- 1-9 submissions
| Use grade_with_rubric (one call per submission)
|
+-- 10-29 submissions
| Use bulk_grade_submissions (concurrent batch processing)
| Set max_concurrent: 5, rate_limit_delay: 1.0
| ALWAYS run with dry_run: true first
|
+-- 30+ submissions OR custom grading logic needed
Use execute_typescript with bulkGrade function
99.7% token savings -- grading logic runs locally
ALWAYS run with dry_run: true first
Strategy A: Single Grading (1-9 submissions)
Call grade_with_rubric once per student:
grade_with_rubric(
course_identifier,
assignment_id,
user_id,
rubric_assessment: {
"criterion_id": {
"points": <number>,
"rating_id": "<string>", // optional
"comments": "<string>" // optional per-criterion feedback
}
},
comment: "Overall feedback" // optional
)
Strategy B: Bulk Grading (10-29 submissions)
Always dry run first. Build the grades dictionary mapping each user ID to their grade data, then validate before submitting:
bulk_grade_submissions(
course_identifier,
assignment_id,
grades: {
"user_id_1": {
"rubric_assessment": {
"criterion_id": {"points": 85, "comments": "Good analysis"}
},
"comment": "Overall feedback"
},
"user_id_2": {
"grade": 92,
"comment": "Excellent work"
}
},
dry_run: true, // VALIDATE FIRST
max_concurrent: 5,
rate_limit_delay: 1.0
)
Review the dry run output. If everything looks correct, re-run with dry_run: false.
Strategy C: Code Execution (30+ submissions)
For large classes or custom grading logic, use execute_typescript to run grading locally. This avoids loading all submission data into the conversation context.
execute_typescript(code: `
import { bulkGrade } from './canvas/grading/bulkGrade.js';
await bulkGrade({
courseIdentifier: "COURSE_ID",
assignmentId: "ASSIGNMENT_ID",
gradingFunction: (submission) => {
// Custom grading logic runs locally -- no token cost
const notebook = submission.attachments?.find(
f => f.filename.endsWith('.ipynb')
);
if (!notebook) return null; // skip ungraded
return {
points: 100,
rubricAssessment: { "_8027": { points: 100 } },
comment: "Graded via automated review"
};
}
});
`)
Use search_canvas_tools("grading", "signatures") to discover available TypeScript modules and their function signatures before writing code.
Token Efficiency
The three strategies have very different token costs:
| Strategy | When | Token Cost | Why |
|---|---|---|---|
grade_with_rubric | 1-9 submissions | Low | Few round-trips, small payloads |
bulk_grade_submissions | 10-29 submissions | Medium | One call with batch data |
execute_typescript | 30+ submissions | Minimal | Grading logic runs locally; only the code string is sent. 99.7% savings vs loading all submissions into context |
The key insight: as submission count grows, sending grading logic to the server (code execution) is far cheaper than bringing all submission data into the conversation.
Safety Rules
- Always dry run first. For
bulk_grade_submissions, setdry_run: truebefore the real run. Review the output for correctness. - Verify the rubric before grading. Confirm criterion IDs, point ranges, and rating IDs match the assignment rubric. Mismatched IDs cause silent failures or incorrect grades.
- Spot-check before bulk. For Strategy B and C, grade 1-2 submissions manually with
grade_with_rubricfirst. Verify in Canvas that the grade and rubric feedback appear correctly. - Respect rate limits. Use
max_concurrent: 5andrate_limit_delay: 1.0(1 second between batches). Canvas rate limits are approximately 700 requests per 10 minutes. - Do not grade without explicit instructor confirmation. Always present the grading plan (rubric mapping, point values, number of students affected) and wait for approval before submitting grades.
Example Prompts
- "Grade Assignment 5 using the rubric"
- "Show me the rubric for the midterm project and grade all submissions"
- "Bulk grade all ungraded submissions for Assignment 3 -- give full marks on criterion 1 and 80% on criterion 2"
- "How many submissions still need grading for the final paper?"
- "Dry run bulk grading for Assignment 7 so I can review before submitting"
- "Use code execution to grade all 150 homework submissions with custom logic"
Error Recovery
| Error | Cause | Action |
|---|---|---|
| 401 Unauthorized | Token expired or invalid | Regenerate Canvas API token |
| 403 Forbidden | Not an instructor/TA for this course | Verify Canvas role |
| 404 Not Found | Wrong course, assignment, or rubric ID | Re-check IDs with list_assignments or list_all_rubrics |
| 422 Unprocessable | Invalid rubric assessment format | Verify criterion IDs and point ranges match the rubric |
| Partial failures in bulk | Some grades submitted, others failed | Check the response for per-student status; retry only failed ones |