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

Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds useful behavioral details beyond annotations: results are 'newest first', include both published and updated items, and can be restricted to a programme. No contradiction with annotations.

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?

Two sentences, front-loaded with the core behavior and ordering, followed by a practical user question. Every sentence adds value without redundancy, and the length is appropriate for the tool's simplicity.

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?

The tool is simple — two optional parameters, both fully documented in the schema — and the description covers the key behavioral aspects: recency ordering, optional programme filter, and intended use. It does not detail the return shape, but for a list-style read-only tool this is not a significant gap.

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 both 'limit' and 'guidance_type' are already documented in the input schema. The description adds only a programme example, not new semantic meaning for parameters, so the baseline 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?

The description states a specific verb and resource: 'NICE guidance published or updated most recently, newest first', with an optional programme restriction. It clearly differentiates from siblings like nice_search_guidance and nice_guidance_by_topic by focusing on recency rather than search or topic.

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 concrete usage context — 'answers what has NICE published this month' and 'shows which treatments have just been appraised for NHS use in England' — which tells an agent when to select this tool. It does not explicitly name alternatives or state when not to use it, but the recency-focused scenarios are clear.

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