eventstream_add_custom_endpoint_source

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

Annotations already indicate it's not read-only (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds value by noting that endpoint_url is deprecated and mentioning the return type 'Updated definition summary', giving context beyond the 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 concise and efficiently structured with docstring-style parameter explanations. No unnecessary sentences; each line adds value.

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 simplicity (3 parameters) and the existence of an output schema, the description covers the action, parameters, and return type adequately. Minor missing context about session prerequisites is not critical for this operation.

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 0%, meaning the schema has no descriptions. The description compensates fully by explaining all three parameters: session_id as 'Builder session ID', source_name as auto-generated, and endpoint_url as deprecated with an alternative.

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 begins with a clear verb and resource: 'Add a custom endpoint source to the eventstream definition.' This distinguishes it from siblings like eventstream_add_custom_endpoint_destination and eventstream_add_sample_data_source by specifying 'custom endpoint source'.

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?

No guidance is provided on when to use this tool versus alternatives such as adding a destination or derived stream. The description implies usage by describing the action, but lacks explicit context or exclusions.

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