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bruchris

Canvas LMS MCP Server

by bruchris
OverviewSchemaSourceRelated ServersScoreDiscussionsAdmin
TypeScript
Hybrid

Update Discussion

update_discussion
Destructive

Change an existing Canvas discussion's title, body, visibility, schedule, or reply rules. Specify course and topic IDs to apply updates.

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. Dates show when Glama detected each change.

  1. 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))$"New value: +"^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:\\.\\d+)?(?:Z))$"
  2. 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."
  3. 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"
+}
  4. First observedv1.18.0

TDQS

B3.2/5.0
Behavior2/5

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

The description only says that a topic is updated, with no mention of overwrite semantics, irreversibility, permissions, or side effects. Annotations mark destructiveHint=true and openWorldHint=true, but the description adds no context about what could be destroyed or what behavior to expect beyond the mutation itself.

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

Conciseness4/5

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

The description is a single front-loaded sentence with no filler or repetition. It is appropriately concise for an update operation, though it could include a bit more scoping detail without becoming bloated.

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

Completeness3/5

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

For an 8-parameter mutation with no output schema, the description gives only the basic purpose and no guidance on results, prerequisites, or destructive behavior. The annotations and fully documented schema cover some of that gap, making the tool minimally callable, but there is no mention of the announcement downgrade caveat or partial-update behavior.

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 the baseline is 3. The tool description names no parameters and does not add semantic context beyond the schema; however, it does not need to compensate for missing schema documentation either.

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?

The description states a specific verb ('Update') and resource ('existing discussion topic'), clearly indicating it modifies an already-created topic rather than creating or deleting one. It is not fully differentiating from siblings like update_module or update_course, but the resource is named.

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

Usage Guidelines3/5

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

No explicit when-to-use guidance or alternative selection is given. The phrase 'existing discussion topic' implies this tool is for modifications after create_discussion and contrasts with get/list/delete siblings, but the description does not name when to prefer this over alternatives.

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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