list_symbols

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

With no annotations, the description carries the full burden, and it does disclose a real behavioral trait: the KiCad 11+ API dependency and the failure mode on KiCad 10. It does not state the read-only/safe nature or any output/permission details, but the version caveat is meaningful context beyond what any structured field provides.

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 sentences, front-loaded with the core action, followed by a compact, high-value caveat and fallback. No padding or restatement of the name.

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 need not be explained. For a no-parameter read tool the description covers purpose plus the important environment caveat and fallback path, making it sufficiently complete, though it could note it only reads the currently open document.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a no-parameter tool is 4. The listed return fields (reference, value, position) are described but belong to the output schema rather than input parameters.

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 ('List symbol instances in the open schematic') and enumerates the fields returned (reference, value, position). It is clearly scoped to schematic symbols rather than board footprints, but it never explicitly contrasts itself with the similar list_* siblings (list_labels, list_footprints), so sibling differentiation stays implicit.

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?

Provides a concrete when-not condition and alternatives: on KiCad 10 this may error, in which case fall back to execute_kipy or read the .kicad_sch file. That is genuinely actionable guidance. It stops short of stating the general when-to-use case versus other listing tools.

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