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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so the safety profile is well covered. The description adds valuable behavioral context beyond those annotations by specifying that the returned body is 'clean Markdown-like', and by listing what is included (metadata, licence, canonical URL), which helps set expectations for the output.

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 no wasted words: the first states the core purpose and output scope, and the second gives precise usage guidance. The most important information is front-loaded.

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 with a single required parameter, and the output schema exists, so return-value documentation is not needed in the description. The description covers the prerequisite workflow and the content envelope, and annotations handle the safety semantics. Nothing essential is missing for an agent to invoke it correctly.

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%, with the slug parameter already documented by name and an example in the schema. The description only reiterates that the lookup is by slug without adding new semantic detail, so it does not compensate beyond the baseline for high schema coverage.

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 uses a specific verb ('Get'), a clear resource ('one complete essay'), and the key identifier ('by slug'), while enumerating the content returned (body, metadata, licence context, canonical URL). It clearly distinguishes this from the many get_* sibling tools because it declares the resource type ('essay/article') and contrasts with list/search operations.

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 explicitly states when to use this tool: 'Use this after `list_articles` or `search_articles` has returned the slug you need.' This provides a clear precondition and names the preceding tools, giving an agent actionable guidance on the correct workflow.

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