calendar_feed_update

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

The description adds substantial context beyond the annotations: it documents the NOT_ENABLED failure mode, describes the exact return shape for enabled and disabled states, and warns that the generated link is a credential that must only be shown to the user. These details are highly relevant for safe invocation and handling of the response.

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 front-loaded with purpose, then failure behavior, return shape, and credential warning. The return-object enumeration is long but justified because no output schema exists; overall the structure is efficient and each sentence carries useful information.

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 low parameter count, full schema coverage, and absence of an output schema, the description is nearly complete: it explains return values, failure conditions, and security handling. The only notable gap is that it does not say whether omitted optional booleans leave existing settings unchanged.

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 input schema already documents both boolean parameters at 100% coverage, including what includeFiscal and includeExpiries mean. The description mentions these fields only as return values and does not add additional parameter semantics such as whether omitted values preserve existing settings.

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 states a specific verb and resource: 'Change what the calendar subscription contains.' It makes clear this is an update to feed content, not a get/enable/disable operation, but it does not explicitly differentiate from the sibling calendar_feed_* tools.

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 precondition 'Fails with NOT_ENABLED when it is off' gives implied usage guidance because the agent learns the feed must already be enabled. However, it never explicitly names calendar_feed_enable as the alternative or says when to use this versus calendar_feed_get/disable.

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