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

The annotations indicate the tool is not read-only and not destructive. The description adds valuable behavioral context by stating that apps without destinations still log events (inspect-only) and that the app is active immediately. This goes beyond the annotations and provides crucial state changes (immediate activation, logging behavior). The only minor gap is not detailing the exact response structure beyond the inbound URL, but the key behavioral outcomes are covered.

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 concise and front-loaded with the core purpose. The first sentence states the primary action and essential inputs. The second sentence adds important behavioral nuance. However, some details like the PATCH example could be seen as slightly verbose, but it conveys a key usage pattern. Overall, it is efficient and structured well.

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 there is no output schema, the description mentions the return value (inbound URL) which is critical for the agent. It also handles the optional parameter behavior and active-immediately status. Sibling tools exist that might serve similar purposes, but the creation context is distinct enough. The description is sufficiently complete for an agent to call the tool correctly.

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?

The schema has 100% description coverage, so parameters are already well-documented (e.g., 'api_key' says it's ignored over stdio, 'source' explains signature auto-detection). The description adds important semantics by clarifying the 'destinations' parameter's optionality and its consequence (logging-only mode). This goes beyond the schema's basic field descriptions, so the description adds meaningful value.

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 ('Create a new app') and specifies the key resources (name, provider source, destinations). It also highlights the unique behavior of creating an app without destinations (inspect-only logging), which distinguishes it from any other tool. This makes the purpose highly unambiguous.

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 implicitly explains when to use this tool: to create an app that can receive events and optionally deliver them. It mentions the alternative of PATCHing the app later to add destinations, but does not explicitly name sibling tools or state when NOT to use it. Still, the context is clear enough for an agent to decide.

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