mcp-sympy

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

No annotations are provided, so the description carries full burden for behavioral disclosure. It only states the action ('substitute') without explaining whether this is a read-only operation, if it modifies the original expression, what the output looks like, or any error conditions. For a tool with two required parameters and no annotation coverage, this leaves significant behavioral gaps.

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 extremely concise at three words ('Substitute in expression'), with zero wasted language. It's front-loaded and efficiently conveys the core action, though this brevity comes at the cost of completeness in other dimensions.

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 complexity of a substitution operation in a mathematical context, no annotations, and rich sibling tools, the description is inadequate. It doesn't explain the tool's behavior, output format (though an output schema exists), or how it differs from similar tools like 'sympy_replace'. For a tool with two parameters and many alternatives, more context is needed.

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 100%, with both parameters ('expr' and 'old_new') documented in the schema. The description adds no additional parameter semantics beyond implying substitution occurs in an expression. Since the schema does the heavy lifting, the baseline score of 3 is appropriate, though the description doesn't compensate with any extra context like format examples or constraints.

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 'Substitute in expression' states the verb ('substitute') and resource ('expression'), making the basic purpose clear. However, it's vague about what exactly is being substituted (parameters vs. symbols) and doesn't distinguish this tool from sibling tools like 'sympy_replace' or 'sympy_xreplace' that might perform similar substitution operations.

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 no guidance on when to use this tool versus alternatives. With many sibling tools in the SymPy server (including 'sympy_replace' and 'sympy_xreplace' that likely handle substitutions differently), there's no indication of context, prerequisites, or comparisons to help the agent choose appropriately.

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