Firefly III MCP Server

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

Annotations declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true. The description adds valuable behavioral context not in annotations: it explains that simple text searches match against description fields, documents the specific query syntax operators (description_contains, amount_more, etc.), and notes that filters can be combined with spaces. It does not contradict annotations.

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?

Excellent structure: front-loaded purpose statement, clear separation between simple and advanced usage, bulleted syntax examples for scannability, and a concise closing instruction on combining filters. No redundant text; every sentence provides actionable information for query construction.

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 tool's complexity (rich query syntax) and lack of output schema, the description appropriately prioritizes documenting the input query language over return values. It comprehensively covers the search DSL. A minor gap is the lack of mention of pagination behavior or result metadata, though page/limit parameters are self-explanatory in the schema.

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?

Despite 100% schema description coverage, the description adds significant value by providing eight concrete query syntax examples (description_contains, amount_is, date_after, etc.) and explaining the fallback behavior for simple text searches. This goes far beyond the schema's basic 'e.g.' example and helps the agent construct valid queries correctly.

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?

Description clearly states 'Search transactions using Firefly III's query syntax' - specific verb (search), resource (transactions), and method (query syntax). This effectively distinguishes it from sibling tools like 'firefly_list_transactions' (simple listing) and 'firefly_get_transaction' (single record retrieval) by emphasizing the advanced search capability.

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 it doesn't explicitly name alternative tools (e.g., 'use list_transactions for unfiltered results'), the extensive documentation of query syntax capabilities provides clear context for when to use this tool versus simple listing operations. It clearly defines the scope of searchable fields and operators, guiding the agent toward using this for filtered/searched retrieval.

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