pcb_get_diff_pair_rules

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

With no annotations, the description carries the burden and does disclose the underlying rule kind and return shape, including that each entry carries an 'enabled' flag (implying disabled rules are also returned). It does not state what happens when no rules exist or whether any permission/active-document prerequisite applies, so it stops short of full disclosure.

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, followed immediately by the disambiguation, which is the right ordering. The 'Returns:' block duplicates part of the output schema, though the field list adds modest value.

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 a no-parameter read tool with an output schema already describing returns, the definition covers what is fetched, what it is not, and where it comes from. The only missing piece is an explicit behavioral edge case (empty result, active document requirement), which is minor at this complexity.

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 the baseline is 4; there is nothing for the description to mis-specify or leave ambiguous. The return-field enumeration it does provide is extra value rather than a parameter 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?

States a specific verb and resource ('Get all differential pair routing rules from PCB design rules') and then explicitly carves out the boundary: these are eRule_DifferentialPairsRouting routing rules, NOT IPCB_DifferentialPair board objects. That distinction is exactly what separates it from the sibling pcb_get_differential_pairs, so an agent can choose correctly from the description alone.

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 'NOT IPCB_DifferentialPair pair objects on the board' clause functions as an explicit exclusion that points the agent toward the pair-object tool for that other need. It is clear context for when this tool is right, though it stops short of naming the alternative tool or stating prerequisites.

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