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

With no annotations, the description carries the full load, and it does disclose the actual decision rules applied (200 mm riser cap, 250 mm going, 2R+G 570–650 mm, 2,100 mm headroom), which is genuine behavioral content. However, it omits critical behavior: whether a non-compliant input returns a report of violations or an error, and how the three optional parameters (baluster gap, balustrade height) affect the verdict.

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?

A single front-loaded sentence with the resource and the governing thresholds packed into a parenthetical that earns every token. Zero filler or restatement of the tool 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?

For a five-parameter, mutation-free evaluation tool with no output schema, the description supplies the standards context an agent needs to trust the tool's scope. The remaining gap is result semantics (pass/fail reporting), which is a minor but real omission given there is no output schema to lean on.

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%, so the parameter definitions already explain each field and its limit; the description only restates a subset of those thresholds. It adds no syntax, units clarification, or defaulting behavior beyond the schema, so the baseline of 3 applies.

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 ('Evaluate') plus a clear resource ('stairway geometry and life safety') and names the governing standard (SANS 10400-M). It is distinguishable from siblings like calculate_sans_fenestration or check_municipal_requirements by domain, though the description never explicitly contrasts itself with them.

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 gives no guidance on when to invoke this versus pre_check_building_plan or get_sans_rules, and no prerequisites (e.g., only residential stairs, only once geometry is known). Usage is only inferable from the tool name and the standards cited.

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