compare_items

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

With no annotations provided, the description carries the behavioral disclosure burden. It discloses that fulltext is truncated, capped per item by max_chars_per_item, and that combined response size is intentionally managed. It also reveals that items can span libraries and that each entry's library_id identifies its source. It could mention error behavior or permissions, but the core behavior is transparent.

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?

The description is dense but mostly efficient. The main action is front-loaded, and the follow-up sentences explain the optional behavior and cross-library capability. A slight restructuring into shorter sentences would improve scannability, but every sentence contributes useful information.

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 batch metadata/fulltext fetching tool with no output schema, the description covers the essential invocation context: what is fetched, when fulltext is included, how it is truncated, and that items can span libraries. It does not describe the response shape or error handling, but an agent has enough to invoke and interpret the call 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 0%, so the description fully compensates. It explains item_keys (several items), include_fulltext (whether to pull PDF text), and max_chars_per_item (per-item cap to keep response manageable). It also clarifies that when fulltext is off, comparison is on metadata, abstracts, tags, and annotations only.

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 opens with a specific verb and resource: 'Fetch metadata (and optionally truncated full text) for several items in one call.' It clearly separates this from single-item tools like get_item and get_item_fulltext by emphasizing multi-item batching and comparison/synthesis. The purpose is unmistakable and actionable.

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 gives clear context for when to use the tool: when you need to compare or synthesize across several items, including across libraries. It also differentiates the two modes (with or without fulltext). However, it does not explicitly state exclusions, such as 'use get_item for a single item' or 'use get_item_fulltext when you need full text for one item.'

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