Send Input to Session

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

Annotations indicate non-destructive (destructiveHint=false) and non-idempotent (idempotentHint=false) behavior. The description adds the detail that a newline is appended by default, but does not disclose other behavioral traits like error handling or character encoding, which would be useful given no output schema.

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 concise with 4 lines plus examples, no fluff. The examples are helpful and placed after the parameter list, though could be slightly more streamlined.

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 the tool's moderate complexity (3 parameters, no output schema), the description covers the essential details (what, how, examples). It lacks return value information but is sufficient for correct invocation.

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?

The input schema has 100% coverage, so baseline is 3. The description adds value by showing examples for each input string format (Python code, shell command) and clarifies the newline default behavior, earning a 4.

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 it sends input to a running session, using specific verb+resource structure. It also distinguishes from sibling tools like 'fc_start_session', 'fc_read_output', and 'fc_close_session' by focusing on input delivery to an active session.

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 provides clear context (sending input to a running session) and examples for Python and Shell, but does not explicitly state when not to use this tool (e.g., for starting a session or reading output) or recommend alternatives.

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