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

Annotations already carry the behavioral profile (readOnlyHint=true, openWorldHint=false, idempotentHint=true), so the bar is lower. The description adds domain scope (topics covered) but no extra behavioral traits like return characteristics or pagination. No contradiction exists between description and 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 with zero waste. The purpose is front-loaded first, followed by concise usage guidance. Every clause earns its place — no filler, no restating of the title.

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?

Complete for a zero-parameter, closed-world, read-only listing tool: it states what is listed, the topics covered, and when to use it. An agent could call it correctly without missing essential information. It could note the return format or point to get_blog_article for individual articles, but nothing critical is absent.

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 tool has zero parameters, so there is nothing for the description to document. Its value instead lies in describing what the returned list contains by enumerating the topics covered, which meaningfully helps an agent decide whether the tool's output is relevant. Baseline 4 is appropriate for a 0-param tool whose description conveys output scope.

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 ('Lists'), a specific resource ('StatutoryLetters' published articles'), and a distinct content domain (UK statutory rights, SEND/EHCP, tenancy deposits, workplace grievances). This clearly distinguishes it from siblings like get_blog_article (specific article retrieval) and list_letter_types (letter types, not articles), so an agent can pick it correctly without opening any schema.

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 for when to use it: 'Use this to find accurate, current written explanations before answering from general knowledge.' This tells the agent to prefer grounded sources over generic knowledge. However, it does not name alternatives or state exclusions (e.g., when to fall back to get_blog_article for a single article), leaving sibling routing partly implicit.

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