Switch which OA all subsequent tool calls default to (until changed or process restarts). In-memory only — does not edit ~/.line-mcp/config.json. Args: - oa_id: OA id from the multi-OA config (use line_list_oas to discover). Returns: { active_oa, display_name }
AI agents use line_use_oa to create or update resources in Line Oa Mcp Ultimate — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Line Oa Mcp Ultimate environment.
This tool creates or modifies application state reversibly—it changes the active OA context without permanently altering any data. If an AI agent switches to the wrong OA, all subsequent operations target that account until corrected. This is a Write-category operation because it alters runtime configuration, though not persisted.
From the tool's definition Tool changes which Official Account (OA) is used as the default for subsequent operations ("Switch which OA all subsequent tool calls default to"). This modifies in-memory state that affects the behavior and targeting of all downstream tool calls.
Documented attack patterns abuse exactly the kind of access line_use_oa gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Line Oa Mcp Ultimate, and nothing reaches the server without passing your rules. This is the rule we recommend for line_use_oa:
{
"version": "1",
"default": "deny",
"tools": {
"line_use_oa": {
"limits": [
{
"counter": "line_use_oa_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}line_use_oa stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Switch which OA all subsequent tool calls default to (until changed or process restarts). In-memory only — does not edit ~/.line-mcp/config.json. Args: - oa_id: OA id from the multi-OA config (use line_list_oas to discover). Returns: { active_oa, display_name }. It is categorised as a Write tool in the Line Oa Mcp Ultimate MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Line Oa Mcp Ultimate MCP server in PolicyLayer and add a rule for line_use_oa: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Line Oa Mcp Ultimate. Nothing to install.
line_use_oa is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the line_use_oa rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for line_use_oa. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
line_use_oa is provided by the Line Oa Mcp Ultimate MCP server (wasintoh/line-oa-mcp-ultimate). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 34 Line Oa Mcp Ultimate tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
34 Line Oa Mcp Ultimate tools catalogued and risk-classified — across an index of 42,500+ MCP servers.