Katzilla MCP

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

Annotations already cover read-only, non-destructive, idempotent, and open-world hints, so the bar is lower. The description adds valuable context beyond annotations: it specifies the return format ('Katzilla envelope { data, quality, citation }'), explains quality scoring ('freshness/uptime/confidence'), and details citation contents ('source URL, license, SHA-256 data hash'). This enriches behavioral understanding without contradicting 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?

The description is efficiently structured in two sentences: the first covers purpose, scope, and source; the second details the return format and its components. Every sentence adds essential information without redundancy, making it front-loaded and appropriately sized for the tool's complexity.

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 moderate complexity, rich annotations (read-only, idempotent, etc.), and the presence of an output schema (implied by 'Returns the Katzilla envelope'), the description is complete. It covers purpose, source, update frequency, and return structure, compensating well for any gaps and aligning with the structured data provided.

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 schema already documents all parameters (city, state, year) with descriptions and defaults. The description adds no additional parameter semantics beyond implying they are used for filtering rates by location and year, which is already clear from the schema. Baseline 3 is appropriate as the schema does the heavy lifting.

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 tool's purpose with specific verbs ('Get federal per diem rates') and resources ('from the U.S. General Services Administration'), including scope details ('lodging and meals & incidentals (M&IE) rates by city and state'). It distinguishes itself from siblings by focusing on GSA per diem data, unlike other housing tools (e.g., HUD-related) or unrelated 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?

The description provides clear context for when to use this tool ('Get federal per diem rates... by city and state') and mentions the source and update frequency ('updates monthly'), which helps in timing decisions. However, it does not explicitly state when not to use it or name specific alternatives among siblings, though the context implies it's for GSA-specific rates.

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