Firefly III MCP Server

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

Annotations already establish this is a non-destructive, idempotent write operation. The description adds value by specifying that partial updates are supported ('name or notes' implies either or both), but does not elaborate on error behavior, authentication requirements, or what constitutes a valid update.

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, efficient sentence with no redundant words. Critical information (operation type, target resource, mutable fields) is front-loaded and immediately accessible.

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?

Given the straightforward CRUD nature of the operation, comprehensive annotations covering safety/behavioral hints, and full schema coverage, the description provides sufficient context for invocation. It appropriately omits return value documentation since no output schema is defined, though it could mention error cases like invalid IDs.

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?

With 100% schema description coverage, the baseline is 3. The description reinforces the purpose of the 'name' and 'notes' parameters by listing them as updatable fields, but adds no additional semantic detail like validation rules, string limits, or format requirements beyond what the schema provides.

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 provides a specific verb ('Update'), resource ('category'), and scope ('name or notes'). The word 'existing' clearly distinguishes this from the sibling create_category tool, while specifying the operation distinguishes it from delete_category 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?

While the word 'existing' implies this is for modifying current categories rather than creating new ones, there is no explicit guidance on when to use this versus firefly_create_category, nor does it mention prerequisites like obtaining the category ID from firefly_list_categories first.

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