Modify pens

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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is known. The description adds real behavioral context beyond that: pens are fixed at 255 and cannot be created, and editing via penTable does not make that set active. These side-effect details are valuable and non-obvious.

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-loaded with the core action followed by the mode semantics, read reference and return shape. It is dense and somewhat run-on, but every clause carries information an agent needs, so little is wasted.

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?

With no output schema, the description carries the return format ({results, activePenTable | penTable}) itself, plus mode behavior and the read alternative. For a mutation tool whose annotations already cover the safety profile, 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 coverage is 67%, but the description meaningfully explains the pens-vs-penTable distinction and its effect on scope, which the schema's terse penTable note only hints at. undoName remains undocumented, keeping it from a 5.

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 and resource ('Changes pen colors, weights and descriptions') and immediately disambiguates by clarifying pens cannot be created. It also names the read counterpart get_attributes, letting an agent distinguish this from sibling attribute tools without opening a 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?

Explains the two operating modes concretely: without penTable the active model pens are changed, with penTable a stored set is edited. It also points to get_attributes for reading current state. There is no explicit exclusion list, but the mode selection guidance is clear enough to route usage.

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