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

With no annotations, the description carries the behavioral burden, and it handles it well: it discloses the destructive nature ('Replace the entire content') and the safety net ('Previous version is saved to history'). It does not cover permissions or failure modes, but the key mutation and recovery behavior is explicit.

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 sentences with no filler; the primary operation is stated first and the version-history fact is a valuable second sentence.

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 simple 3-parameter mutation tool with no annotations and no output schema, the description covers required semantics and the main side effect. The only notable omission is an explanation of the optional changeNote, but this is a low-severity gap given the required params are obvious.

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?

Only content has a schema description (33% coverage), and the tool description adds no new details about documentId or changeNote. The phrase 'entire content' restates the content parameter's 'New full content' rather than explaining how to format it or what changeNote is for.

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 uses a specific verb ('Replace'), names the resource ('existing text document'), and clarifies scope ('entire content'), distinguishing it from append_to_document and update_document_metadata. There is no ambiguity about what operation is performed.

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 phrase 'Replace the entire content' implies this tool is for full-content overwrites rather than appends or metadata edits, but it never states the alternative conditions or explicitly says to use append_to_document for additions. An agent must infer the selection rule from sibling names.

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