femm_eval

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

No annotations are present, so the description carries the full burden and does well: it discloses the return convention ('tab-separated reply parsed to numbers/lists'), that statements yield null while expressions yield values, the one-line constraint, and that variables persist per session. Missing only error/failure behavior and any auth or side-effect notes.

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?

Front-loaded with the core action, then constraints, then concrete examples. Every sentence carries information; the worked examples ('mo_getpointvalues(0,0)[1]') are genuinely useful rather than filler.

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?

No output schema exists, and the description covers return shape, statement-vs-expression semantics, and the session persistence model, so an agent can call it correctly. The main residual gap is the 'session' parameter's semantics, which neither schema nor description explains.

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% for two parameters. The description implicitly clarifies 'expression' (one line, newline rejected) but never explains the 'session' parameter, its meaning, its default, or how sessions relate across calls beyond 'variables persist between calls in the same session.' Partial compensation for a real coverage gap.

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?

Specific verb+resource: 'Evaluate ONE LINE of MicroPython inside FEMM and return its value.' It distinguishes itself from siblings both by language ('MicroPython' vs the Lua sibling) and by naming femm_run_script as the multi-line alternative.

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?

Explicit when-not guidance: 'A newline is rejected: for multi-line code use femm_run_script.' This routes the agent cleanly. It does not, however, address the other plausible alternatives (femm_call, femm_run_lua, femm_api_get), so the routing picture is not fully closed.

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