post-to-slacklisted

# Post to Slack Resolves a channel name (or a user name for a mention) to its Slack ID before posting — the Slack MCP connector's send/search tools need IDs, not display names, and IDs are not stable across workspaces. ## Steps 1. Determine the message body and the target channel. If the caller (a direct user request, or another skill such as `report-pbl-progress`) already gives an explicit channel ID (`C...`) and/or an already-resolved mention (`<@U...>`), skip straight to step 4 — don't re-resolve what's already unambiguous. 2. If the channel is given by name rather than ID, resolve it with the Slack MCP connector's `slack_search_channels` tool and take the matching channel's ID. If more than one channel plausibly matches, ask the user rather than guessing. 3. If a mention is wanted and given by name rather than user ID, resolve it with `slack_search_users` and format it as `<@USERID>` inline in the message text — Slack does not render `@name` as a mention, only the raw `<@ID>` form works. 4. Post with `slack_send_message` (`thread_ts` for a thread reply, `reply_broadcast` to also surface a thread reply in the channel). Return the message's permalink to the caller. ## Reference ### Failure modes - **Channel not found**: `slack_search_channels` found no match — confirm the exact channel name with the user; don't guess a close match. - **User not found**: same for `slack_search_users` when resolving a mention. - **Message too long