Remove all messages from a named Unreal Engine Message Log listing, such as PIE or MapCheck, to reset it and see cleared and remaining message counts.
Clear all messages from a named engine Message Log listing.
Returns: { cleared: bool, log_name: string, cleared_count: int, messages_after: int }
| Name | Required | Description | Default |
|---|---|---|---|
| log_name | Yes | The message log listing name (e.g. "PIE", "MapCheck", or a custom name). |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds genuine value by spelling out the return shape (cleared, cleared_count, messages_after) in the absence of an output schema, and the word 'all' clarifies that this is a wholesale purge rather than a filtered delete.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two compact lines: purpose first, return shape second. No filler, no restated name, and the most decision-relevant fact (clearing all messages) is front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a single-parameter destructive tool with full annotation coverage and no output schema, the description supplies the return shape an agent would otherwise lack. It is close to complete, though it omits the irreversibility/permission caveat that a destructive operation would ideally state even alongside destructiveHint.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% and only one parameter exists, so the schema already documents log_name fully. The description's phrase 'named engine Message Log listing' mirrors the schema wording without adding format, valid-casing, or default-value guidance. Baseline 3 is appropriate when the schema does the heavy lifting.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb ('Clear'), the exact resource ('all messages'), and the scope ('from a named engine Message Log listing'), which cleanly separates it from siblings like get_message_log_entries and add_message_log_entry. An agent can tell what this does without opening the schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The verb 'clear' makes the intent self-evident, but the description offers no explicit when-to-use guidance, no prerequisites, and never names the read sibling (get_message_log_entries) that an agent should pick instead when it does not want to destroy messages. Usage is implied rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.