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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so safety is covered. The description adds genuinely new operational context — 'Costs no model tokens' — which informs the agent's cost trade-off against the sibling tools. It doesn't mention pagination or result-size limits, hence not a 5.

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 tight sentences with zero filler: what it returns first, then when to use it, then the cost note. Front-loaded and appropriately sized for a simple list tool.

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?

An output schema exists, so return values need no explanation, and annotations cover the safety profile. The only gap is that the optional category filter is absent from the description, leaving the agent to discover filtering from the schema alone.

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 description never mentions the optional 'category' filter. With schema description coverage at 100%, the schema fully documents the parameter (including case-insensitive matching and examples), so the baseline 3 applies — the description adds nothing but loses nothing.

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 ('List the canonical engineering questions Balford's knowledge base is built around'), plus scope ('grouped by process family') and payload ('URL of the answer page'). This is clearly distinct from ask_balford_engineering and search_balford_material.

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 explicit usage context: 'find the right published answer before asking a free-form question' and 'see whether a topic is covered at all'. It gestures at the alternative (free-form question) but never names ask_balford_engineering or search_balford_material, so routing still requires inference.

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