session_write_file

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

With no annotations, the description discloses a key behavioral constraint: 'relative path, no escapes.' This tells the agent the tool is a write operation and provides a safety-relevant restriction, but it does not mention whether existing files are overwritten or how invalid paths are handled.

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 concise, front-loaded sentences with no filler. The first sentence states the action, the second gives the purpose. Every word earns its place.

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 three-parameter write tool with an output schema (so return values need no explanation), the description covers purpose, usage, and key constraints. It lacks details about overwrite behavior and session validity, but is largely sufficient for straightforward invocations.

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 adds meaning to 'path' (relative) and 'content' (seed input data), but leaves 'session_id' unexplained. The param names are self-explanatory, but not all parameters receive contextual detail.

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 ('Write') and resource ('file into a session workspace'), and clarifies the relative path and no-escape constraints. It clearly distinguishes this from sibling tools like session_read_file (reading) and session_files (listing).

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 explicitly states a use case: 'Use this to seed input data for executed code.' This provides clear context for when to use the tool, though it does not mention exclusions or alternative tools by name.

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