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bruchris

Canvas LMS MCP Server

by bruchris
OverviewSchemaSourceRelated ServersDiscussionsAdmin
TypeScript
Hybrid

Update Discussion

update_discussion
Destructive

Update an existing discussion topic.

Instructions

Update an existing discussion topic.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
titleNoNew title for the discussion topic
messageNoNew body text (supports HTML)
topic_idYesThe Canvas discussion topic ID
course_idYesThe Canvas course ID
publishedNoPublish or unpublish the topic
delayed_post_atNoISO 8601 datetime to schedule the topic for future posting
is_announcementNoWhen true, requests marking the topic as an announcement. Canvas silently downgrades this to a plain discussion topic (no error) if the caller lacks announcement permission in the course — check the response's own `is_announcement` field rather than assuming the request was honored.
require_initial_postNoRequire students to post before seeing replies

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed4 schema fields changedv1.18.15
    • addedInput schema / properties / course_id / anyOf
      Added value: +[
+  {
+    "exclusiveMinimum": 0,
+    "maximum": 9007199254740991,
+    "type": "integer"
+  },
+  {
+    "pattern": "^[1-9][0-9]{0,18}$",
+    "type": "string"
+  }
+]
    • removedInput schema / properties / course_id / type
      Removed value: -"number"
    • addedInput schema / properties / topic_id / anyOf
      Added value: +[
+  {
+    "exclusiveMinimum": 0,
+    "maximum": 9007199254740991,
+    "type": "integer"
+  },
+  {
+    "pattern": "^[1-9][0-9]{0,18}$",
+    "type": "string"
+  }
+]
    • removedInput schema / properties / topic_id / type
      Removed value: -"number"
  2. Changed1 schema field changedv1.18.11
    • changedInput schema / $schema
      Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"
  3. Changed1 schema field changedv1.18.8
    • changedInput schema / properties / delayed_post_at / pattern
      Previous value: -"^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"New value: +"^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:\\.\\d+)?(?:Z))$"
  4. Changed1 schema field changedv1.18.4
    • changedInput schema / properties / is_announcement / description
      Previous value: -"When true, marks the topic as an announcement"New value: +"When true, requests marking the topic as an announcement. Canvas silently downgrades this to a plain discussion topic (no error) if the caller lacks announcement permission in the course — check the response's own `is_announcement` field rather than assuming the request was honored."
  5. Changed2 schema fields changedv1.18.3
    • addedInput schema / properties / delayed_post_at
      Added value: +{
+  "description": "ISO 8601 datetime to schedule the topic for future posting",
+  "format": "date-time",
+  "pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$",
+  "type": "string"
+}
    • addedInput schema / properties / is_announcement
      Added value: +{
+  "description": "When true, marks the topic as an announcement",
+  "type": "boolean"
+}
  6. First observedv1.18.0

TDQS

C2.8/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already disclose destructiveHint=true and openWorldHint=true, so the safety profile is partly covered. The description adds nothing beyond 'update'—it does not explain partial vs. full replacement semantics, permission requirements, side effects on existing entries, or how omitted fields are treated.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness3/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The single sentence is concise and front-loaded, but for an 8-parameter mutation tool it is under-specified rather than appropriately sized. It mirrors the title almost exactly, so it provides minimal structural value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given a destructive mutation with 8 parameters, no output schema, and only openWorld/destructive annotations, the description leaves critical gaps: whether the update is partial or full, what permissions are needed, and what happens to unmentioned fields. It is not complete enough for confident invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so each of the 8 parameters is already documented in the input schema. The description adds no parameter-level meaning beyond what the schema provides, making the baseline of 3 appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Update') and resource ('existing discussion topic'), which is clear and distinguishable from create/delete siblings by action. However, it adds no sibling differentiation and simply restates the tool name/title rather than expanding on what updating entails.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides no when-to-use guidance, no alternatives (e.g., create_discussion, delete_discussion), and no prerequisites. The agent must infer that this tool is for modifying an existing topic rather than creating or deleting one.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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