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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the agent knows this is a non-destructive write. The description adds no behavioral context beyond the save operation itself — no deduplication, overwrite, or side-effect information. It does not contradict the annotations, but it contributes nothing beyond them.

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?

One sentence with zero waste: it front-loads the operation ('Save a bookmark URL'), lists the optional fields, and omits redundant detail. It is efficiently scannable.

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 create tool with full schema coverage and no output schema, the description covers the operation and core parameters adequately. It could mention edge behaviors like duplicate handling, but those are not necessary for a basic invocation.

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 all five parameters are already well documented. The description adds a light confirmation by listing the optional fields and implying url is required, but it provides no additional semantic detail beyond the schema.

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 ('Save') and resource ('bookmark URL'), then enumerates the optional fields (title, description, category, tags). It clearly identifies the operation as creating a bookmark and is easily distinguishable from sibling tools like delete_bookmark and list_categories.

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 by the verb and resource: use this to save a bookmark URL. However, it does not explicitly state when to use this versus alternatives, mention prerequisites (e.g., whether categories must already exist), or give exclusions.

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