Evaluate Emacs Lisp

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

With no annotations, the description carries the full behavioral burden. It gestures at safety with 'trusted local' but never warns that this executes arbitrary code with full server-side side effects, nor explains timeout or output-truncation behavior. For an eval tool this is a significant disclosure gap.

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?

A single, front-loaded sentence with no filler. It is efficient, though its brevity is part of why behavioral and parameter context is missing.

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?

An output schema exists so return values needn't be explained, but for an arbitrary-code-execution tool with zero annotations the description should disclose side effects, timeout semantics, and output limits. Those omissions leave an agent under-informed about the two undocumented parameters and the tool's blast radius.

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 coverage is only 33%: 'expression' is documented in the schema, but 'timeout_ms' and 'max_output_chars' carry no description anywhere. The description adds nothing about these controls, so it fails to compensate for the coverage gap despite their relevance to a long-running or chatty evaluation.

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?

States a specific verb and resource: evaluate exactly one Emacs Lisp form against a running Emacs server. The 'exactly one form' constraint and the runtime target are clear. No siblings exist to differentiate from, so it doesn't need comparative wording.

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 'already-running trusted local Emacs server' implies a precondition (a server must exist and be local/trusted), which is useful routing context. However, it never states when to reach for this tool versus other execution paths, nor any exclusions or failure conditions.

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