Get one article

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

Despite readOnlyHint already being provided, the description adds valuable context: API key requirement for unpublished articles, published ones readable without, and error conditions. This goes beyond annotations and matches the tool's actual behavior.

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?

Though slightly verbose with four sentences, each sentence contributes context: purpose, usage, behavior, auth, errors. It is front-loaded with the core action and not redundant given the added info beyond annotations.

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?

For a simple tool with one parameter and no output schema, the description covers all critical aspects: what it does, when to use it, read-only nature, auth requirements, return content, and failure modes. It is essentially complete for an agent to invoke 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?

The schema already fully describes 'slug' with explanation and example, and the description adds no new parameter-level detail. Baseline of 3 is appropriate given 100% 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 clearly states the action ('Fetch a single article by slug') and distinguishes it from listing tools that omit bodies, making it unambiguous and aligned with its sibling tools.

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?

It explicitly tells when to use the tool ('after list_my_articles or search_articles has given you a slug') and explains the rationale for fetching one at a time, clearly contrasting with alternatives.

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