Design single-stub matching (distributed)

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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds real substance on top: returns ALL solutions in wavelengths, degrees and physical length (with eps_eff/velocity_factor), plus verification and matched bandwidth, and states component ordering (load → source) for downstream tools. With no output schema, this carries the return-value burden well.

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?

Three dense sentences, front-loaded with purpose and the computed quantities before the return/chaining detail. Nearly every clause carries information, though the parenthetical citations and return enumeration make it slightly heavier than needed.

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?

For an 11-parameter, nested-object tool with no output schema, the description covers what the tool computes, what it returns, and how the result plugs into sibling tools. It does not explain defaults/fallbacks for the many optional impedance and line parameters, but those are fully covered by the schema.

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 100%, so all 11 parameters are already documented, which sets the baseline at 3. The description only loosely links parameters ('open- or short-circuited stub (shunt or series)', 'when frequency is given') without adding format or constraint detail beyond the schema.

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?

Names a specific verb+resource ('single-stub tuner design'), specifies exactly what is computed (distance d from load, stub length ℓ, open/short, shunt/series), and cites Pozar §5.2. It is clearly distinguishable from design_l_match, design_pi_t_match and design_quarter_wave.

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?

Gives a positive usage context ('microstrip/coax stub tuners and textbook Smith chart stub problems') and notes the output feeds analyze_circuit / render_smith_chart, which is genuinely useful chaining guidance. It stops short of naming when to prefer a sibling topology (L-match, Pi-T, quarter-wave) instead, so no explicit exclusions.

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