ClickUp vs Redmine

ClickUp

The hosted MCP server uses OAuth 2.1 with PKCE, dynamic client registration and read and write scopes, and works on the Free Forever plan. Without the Everything AI add-on, MCP calls are capped at 100 to 25,000 per rolling 24 hours by plan. No API changelog, deprecation policy, official SDK or SLA was found.

Redmine

Redmine's REST API covers issues, projects, time entries and 20 other resources, and versions 6.1 and later add OAuth 2 with one scope per permission. The software is free under the GPL. No OpenAPI document exists, most errors return a bare status code, and 24 security advisories were published in twelve months, two rated critical.

ClickUp

1. Connect to https://mcp.clickup.com/mcp with OAuth 2.1 and PKCE. API keys and REST OAuth tokens are refused on the MCP server
2. Pass workspace_id on every MCP call when the user belongs to more than one Workspace, as ClickUp's own skills instruct
3. Budget MCP calls. Each tool call counts against the rolling 24-hour cap, and RATE_LIMIT_EXCEEDED returns retryAfter
4. On the REST API read X-RateLimit-Remaining and X-RateLimit-Reset, and page Get Tasks with page at 100 tasks a page
5. Treat team_id in API v2 as the Workspace ID, and send dates as Unix milliseconds

Redmine

1. Ask an administrator to tick Enable REST API under Administration, Settings, API. It is off by default and every call fails until then
2. Send the key in the X-Redmine-API-Key header, never as the key query parameter, and set Content-Type: application/json on every POST and PUT
3. Add status_id=* to issue lists. The default returns open issues only, 25 a page with a maximum of 100
4. Comment on an issue by sending notes in a PUT to /issues/<id>.json. There is no separate comment endpoint
5. A DELETE on a project through the API skips the confirmation the web page asks for, so run the agent as a non-administrator user