lines.insert

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

With no annotations provided, the description carries full burden. It discloses that insertion is line-based, supports appending via line=totalLines+1, and requires no hash. However, it does not explain behavior for invalid line numbers (beyond schema min=1), whether the operation is destructive, or what the tool returns. Partial disclosure.

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 two short sentences, front-loaded with the core action, and contains no fluff. Every sentence adds value: the first states purpose, the second adds behavioral nuance.

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 5 parameters (3 required), no output schema, and no annotations, the description covers the basic insertion scenario but omits explanations for 'vault' and 'dry_run', and doesn't specify return value or side effects. Adequate for simple use but not fully complete for a parameter-rich tool.

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 0%, so the description must compensate. It explains 'line' (1-based, append trick) and implies 'content' is the text to insert, but does not clarify 'file', 'vault', or 'dry_run'. For 5 parameters, only 2 are partially covered, leaving significant gaps.

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 action: 'Insert content before line N (1-based).' It distinguishes itself from sibling tools like 'lines.replace' by specifying insertion before a line, and even handles appending with 'Use line=totalLines+1 to append.' This provides a specific verb and resource, making purpose unambiguous.

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 gives explicit usage for inserting and appending, and notes that 'No hash precondition required,' which tells users they don't need a hash. However, it does not explicitly contrast with alternative tools (e.g., when to use lines.insert vs lines.replace) or provide when-not-to-use guidance.

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