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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the description's job is added context. It delivers that by disclosing the actual heuristics applied (two-thirds to three-quarters of furniture width, 57-60 inch centering height) and by noting the answer includes a source link, which tells the agent what will come back. The link mention sits slightly uneasily with openWorldHint=false but describes answer content, not external fetching, so it is not a contradiction.

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 core output set is front-loaded in a single dense sentence and the second sentence adds provenance context compactly. Wording is slightly tangled (nested parentheticals and mixed 'how wide/how high/how tall'), but no sentence is wasted or redundant.

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?

With three simple parameters, full schema descriptions, and no output schema, the description carries most of what an agent needs: it enumerates the three returned measurements and the rules behind them. Minor gaps remain around what the 'rule of thumb' returns when the range is ambiguous, but nothing blocking is missing.

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% and each parameter already documents its meaning and units in inches, so baseline is 3. The description adds only indirect meaning by tying the width rule to the width input and the centering rule to the top input; it does not clarify edge cases such as how the 57-60 inch range is resolved or default behavior beyond the schema's own 'Default sofa.'

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?

The description names a concrete resource and computation: recommended wall art width over a sofa/bed/console, hang height, and max height for 57-60 inch centering. That is a specific verb-plus-output statement rather than a restatement of the title. It does not name any sibling (e.g., curtain_length or bathroom_mirror_size), so sibling differentiation is left 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?

Usage is implied by the furniture enum and inputs ('over a sofa, bed or console'), so an agent can infer the scenario. There is no explicit when-to-use/when-not statement and no alternative tool is named for adjacent questions like spacing multiple pieces or hanging height without a furniture width. Guidance is adequate but inferred.

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