Add papers to library

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

Annotations already declare idempotentHint=true and destructiveHint=false, but the description goes further by spelling out what that idempotency means in practice: 'Papers already in the library are not duplicated.' That is concrete semantic content beyond the hint flags, and it tells the agent the call is safe to repeat. Gaps remain around failure modes (invalid bibcodes, non-existent library ID, permission failures) and what is returned.

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?

Three short sentences, front-loaded with the action and target, and no filler. The middle sentence is largely a restatement of the two required parameters and could be trimmed, which keeps it from a 5.

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 small two-parameter tool with clean annotations, the description covers purpose, inputs, and dedup behavior. However, with no output schema, it never says what the call returns (e.g., how many papers were added versus skipped) or how partial failures are handled, which an agent needs to interpret results.

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 coverage is 100%, so both parameters are already documented in the schema, including the pointer that library_id comes from list_libraries. The description's 'Provide library ID and list of bibcodes' merely restates the schema without adding format, limits, or edge-case meaning. Baseline 3 is appropriate when the schema carries the load.

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 states a specific verb and resource ('Add papers to an existing library in the user's ADS account'), and the word 'existing' implicitly separates it from create_library and get_library_papers. It stops short of naming any sibling explicitly, so an agent must still infer the boundary from the surrounding tool list.

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?

Usage is implied rather than stated: the tool only applies to a library that already exists, which hints that create_library must have run first, and the schema note '(from list_libraries)' points to the lookup step. There is no explicit when-not guidance (e.g., what to do for a new library, or whether to use this versus any bulk import path) and no prerequisites such as authentication or ownership of the library.

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