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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds substantial behavioral context: exact formulas, default assumptions, edge clearance handling, lap splice logic, waste allowance, and ASTM A615 weight basis.

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 definition is front-loaded with the purpose, then packed with formula details. It is dense and every sentence contributes, though the single-paragraph formula block could be more readable if structured as separate lines or bullets.

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 complex calculator with 8 fully described optional parameters, read-only annotations, and no output schema, the description supplies enough detail to call it correctly. It names the outputs (bar count, splices, linear feet, sticks, weight) and the governing formulas.

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 the baseline is 3. The description goes beyond the schema by linking parameters through formulas: clear span from width/length and edge clearance, bar count from spacing, lap length from bar diameters, and weight from ASTM A615 lb/ft.

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: calculates rebar quantity for a rectangular slab grid, including bar count, lap splices, linear feet, sticks, and weight. This clearly distinguishes it from sibling calculators like calc_concrete_slab and calc_board_foot.

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 clear context by specifying it is for a rectangular slab grid and gives the complete formula, so an agent knows when it applies. However, it does not name alternatives or state when not to use it, such as for irregular slabs or other rebar shapes.

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