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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered structurally. The description adds a genuinely new behavioral trait not in the annotations: 'the formatted result may be stored in an operational cache,' disclosing an internal side effect. The account/publication disclaimer largely restates the read-only hint.

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 action and no wasted preamble. The second sentence carries two distinct points (cache side effect and scope disclaimer) that could be slightly tighter, but the structure is efficient.

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 10-parameter, fully-described, annotation-rich tool with no output schema, the description is nearly sufficient. It implies the return value (a formatted citation) and discloses caching. It could note the default style behavior or the enum breadth, but nothing essential for correct invocation is missing.

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%, so the schema already documents all 10 parameters, including the 64-value style enum and its apa default. The description only echoes three field names (title, authors, year) and adds no format-level or style-selection guidance. 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?

States a specific verb+resource: 'Format citation data (title, authors, year, etc.) into a specific citation style.' The output is clear. It does not name siblings check_references or search_citations, but the name and purpose are distinct enough that an agent can distinguish it without opening the 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?

No explicit when-to-use guidance or routing to the sibling tools. The clause 'does not publish content or modify a user account' is a scope disclaimer, not a selection criterion, and leaves the agent to infer when format_citation is preferred over search_citations or check_references.

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