Intercom: authenticate with an access token header

[staging-devin-ai-integration]

Summary

Intercom's hosted MCP (https://mcp.intercom.com/mcp) has never connected via OAuth from Devin: its Dynamic Client Registration rejects our callback (400 invalid_redirect_uri — "Redirect URI https://api.devin.ai/mcp/oauth/callback is not in the allowlist", verified live). A url-only declaration is treated as OAuth-connectable, so users hit "Failed to start OAuth flow" every time.

Declare the header Intercom's other supported auth mode uses, matching the zapier/square/plaid/perplexity/corridor plugins:

"headers": { "Authorization": "${INTERCOM_AUTHORIZATION}" }

The credential value is the full header value, Bearer <Intercom access token> (verified live: bearer accepted; bare token → 401). Nothing prepends Bearer , same as the other ${<PLUGIN>_AUTHORIZATION} plugins.

python3 scripts/validate.py --fix passes (170 entries). Re-do of usacognition/devin-marketplace#13, which landed in the wrong (unused) repo; the webapp pins this one (MARKETPLACE_REPOSITORY_URL). Companion webapp change for the legacy marketplace row: usacognition/devin-webapp#71745.

Link to Devin session: https://staging.itsdev.in/sessions/3b9044c1d90c48c88784ffc924e9b913
Open in Devin Desktop: https://staging.itsdev.in/desktop/session/3b9044c1d90c48c88784ffc924e9b913?variant=devin-insiders
Requested by: @AidanBlumLevine

---

Note

Devin errored when opening this Pull Request as AidanBlumLevine.
As a fallback, Devin opened this PR as itself.

---

Devin Review

Status	Commit
⚪ Not started	—

Run Devin Review

[staging-devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

---

Original prompt from Aidan

SYSTEM:
<latest_message>
Aidan Blum Levine (U095PKFHU6A) [ts=1788550290.790849]: @Devin can you see what happened in the logs?
</latest_message>

=== BEGIN THREAD HISTORY (in #eng-plugins) ===
Nader Dabit (U0ABT800W1W) [ts=1788548454.735409]: Issue with plugins from startup user

[Slack unfurl — this is an automatic link preview, not a user message]
Quote of conversation (https://cognition-ai.slack.com/archives/C0BMB86P9SB/p1788545616740879?thread_ts=1788545616.740879&amp;cid=C0BMB86P9SB):
> From Herbie
> <!channel> Looks like several of our plugins randomly disconnected. I was able to re-connect all of them except Intercom and Exa, even after uninstalling and re-installing. They all show an error when I click reconnect. Could you take a look? I also tested in a Devin session to confirm it was not connected. Trying to complete setup through the link Devin sent me showed an error message: "Failed to start OAuth flow".
> Posted on September 04, 2026 at 06:13 PM

Aidan Blum Levine (U095PKFHU6A) [ts=1788550290.790849]: @Devin can you see what happened in the logs?
=== END THREAD HISTORY ===
Channel ID: C0B15442C4E
Thread URL: https://cognition-ai.slack.com/archives/C0B15442C4E/p1788548454735409?thread_ts=1788548454.735409&amp;cid=C0B15442C4E

The <latest_message> is the message that you should use to guide your goals + task for this session, and you should use the rest of the slack thread as context.
A [ts=...] marker on a Slack message is that message's timestamp. To act on a specific message with the slack tool (e.g. adding an emoji reaction via the reaction command), pass that value as timestamp along with the Channel ID — no extra lookup call is needed.