update_ical_subscription

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

Annotations declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavior: a URL change forces a full re-sync on the next poll. It does not say whether omitted fields are left untouched or require permissions, but the added side-effect disclosure is meaningful.

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?

Two short sentences, zero filler, and the core action is front-loaded before the re-sync caveat. Every clause earns its place.

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?

For a mutation tool with full annotation coverage, no output schema, and 100% schema coverage, the description supplies the key behavioral consequence of a URL change. Minor gaps remain: partial-update semantics for omitted fields and any auth/permission requirements are unaddressed.

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 all three parameters are already documented in the schema; the description's mention of label and feed URL largely restates those properties. Baseline 3 applies since the schema does the heavy lifting, though the URL/re-sync linkage adds a little meaning.

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?

States a specific verb and resource ('Update an external iCal feed subscription') and enumerates the two mutable fields (label, feed URL), which is far more than a tautology. The re-sync note implicitly separates it from sync_ical_subscription, but no sibling is named outright, so it stops short of full differentiation.

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?

'Change its label or its feed URL' implies the context in which the tool is used, but there are no explicit when/when-not statements, no prerequisites, and no routing to alternatives — notably it never says to use sync_ical_subscription if you want an immediate re-sync rather than waiting for the next poll.

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