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

Annotations already declare mutation safety and idempotency, but the description adds critical behavioral context beyond them: fuzzy title resolution can silently choose wrong versions, bad matches are expensive to undo, duplicate items are skipped, and results include honest per-item counts.

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?

Front-loads purpose and usage rules, then layers in disambiguation risks, return shape, and follow-up status handling. Despite being dense, every sentence provides actionable guidance for correct invocation.

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 bulk mutation tool with no output schema: it explains the return object shape, the default status behavior, error modes, and the follow-up tool for status changes. Annotations plus schema cover the rest.

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 baseline is 3. The description meaningfully strengthens parameter guidance by saying to always pass year and external_id whenever known, explaining why those fields prevent silent misresolution—an important layer beyond the schema's optional phrasing.

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, and scope: add up to 250 items to the library in one call. It explicitly distinguishes itself from the add_item sibling by warning against looping.

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?

Gives clear when-to-use guidance (lists of more than 3 items), an explicit alternative to avoid (never loop add_item), and a prerequisite workflow for ambiguous titles (resolve via lookup_item). It also routes status changes to bulk_update_status.

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