GTM API / Check target reachability

Check whether a target person can be reached from this account (not blocked / out of network). Probes from the account itself; when the platform cannot obtain an independent second viewpoint the outcome is inconclusive rather than a guess. Contract: - MCP tool check_linkedin_account_target_block, registry package mcp.linkedin/linkedin_accounts, mount linkedin.accounts. - Operation action, response envelope action. - Flags: paced: a call spends the self_account_sync smart-limit bucket of the account it runs on, and calls of one bucket are spaced per account. A short wait is slept by the server; a longer one answers 429 rate_limited with context.retry_after, and the same call succeeds from that moment. Parallel calls on one account queue behind each other.