MCP File Compaction

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden. It discloses key behavioral traits: it writes content, creates the file if missing, makes it active, and creates parent directories. However, it lacks details on permissions, error handling, or what 'active' means operationally, leaving gaps for a mutation tool.

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?

The description is appropriately sized with three concise sentences, each adding value: the core action, the active file effect, and directory creation. It is front-loaded with the primary purpose, and there is no wasted text or redundancy.

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?

Given a mutation tool with no annotations and no output schema, the description is moderately complete. It covers the basic behavior and side effects (e.g., creating directories), but lacks details on return values, error cases, or interaction with sibling tools, which could be important for an agent.

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 description coverage is 100%, so the schema already documents both parameters ('path' and 'content') adequately. The description adds no additional meaning beyond what the schema provides, such as format examples or constraints, meeting the baseline for high schema coverage.

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?

The description clearly states the specific action ('write content to a file') and resource ('file'), and distinguishes it from siblings like 'read_file' or 'edit_file' by emphasizing creation and making it active. The phrase 'creating it if it doesn't exist' adds specificity beyond just 'write'.

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 description implies usage for writing or creating files, but provides no explicit guidance on when to use this tool versus alternatives like 'edit_file' or 'read_file'. It mentions the file becomes active, which hints at context, but lacks clear when/when-not instructions or named alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.