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

Annotations already cover the read-only, idempotent, non-destructive profile, so the bar is lower, but the description still adds real value: it discloses the return value (a link to the item page) and the conditional side effect of opening the item in the app. It does not cover failure behavior when an item is missing, which limits it to a 4.

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, followed by the trigger condition and the return value. Nothing redundant.

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?

There is no output schema, and the description fills that gap by explaining what the caller gets back (a link, plus direct opening when the app is the client). Combined with 100% schema coverage on the three parameters, an agent has everything needed to invoke it 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 100%, so the baseline is 3; the id/title precedence and ambiguous-match behavior are fully documented in the schema itself. The description adds nothing about parameters beyond 'one item', which is adequate since the schema does the work.

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 — 'Open one item from the user's library in Achriom' — which is unambiguous. It does not explicitly contrast with close siblings like get_details or lookup_item, so an agent must infer the difference, keeping it below a 5.

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?

'Use when they ask to see, open, go to or pull up an item' gives concrete triggering user phrasings, which is strong positive guidance. No exclusions or alternatives (e.g. when to prefer get_details instead) are offered, so it stops short of a 5.

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