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

Annotations already indicate this is not read-only and not destructive. The description adds that it's for the caller, but does not disclose other behaviors such as handling duplicate saves or permission requirements.

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 a single sentence of six words, containing zero wasted information. It is efficiently front-loaded.

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 simple save action, the description is adequate but lacks details on behavior when saving an already-saved item, response format, or error conditions. Given the presence of both 'save_item' and 'remove_saved_item' siblings, more context would be helpful.

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 50% (item_id has description, item_type lacks one). The description does not provide any additional meaning beyond the schema, failing to compensate for the missing item_type description.

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 clearly states the action (bookmark), the resources (episode or lesson), and the target (caller). It distinguishes from siblings like 'remove_saved_item' and 'get_saved_items'.

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 implies usage when bookmarking is needed, but provides no explicit guidance on when to use this tool versus alternatives like 'get_saved_items' to view bookmarks or 'search_episodes' to find content.

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