update-subscription

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

The description indicates a mutation action ('renew', 'extends') which aligns with destructiveHint=true. It adds context about expiration behavior and the need to call before expiry. No contradiction with annotations (readOnlyHint=false, destructiveHint=true) is present.

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 well-structured with a clear purpose sentence followed by rationale and a tip section. It is slightly lengthy but efficiently communicates key information without unnecessary fluff.

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 complexity (nested body, many parameters, subscription management), the description covers the essential: purpose, renewal reason, body format, and reminder to check limits. It references external docs for details, which is acceptable without an output schema.

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 description adds value by summarizing the body format ('Body: { expirationDateTime (ISO 8601, new expiry) }'), which complements the schema's high coverage (75%) of parameter descriptions. It provides practical guidance beyond what the schema offers.

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 explicitly states 'Renew a subscription by extending its expiry time', which is a specific verb (renew) and resource (subscription). The tool is clearly distinguished from sibling tools like create-subscription and delete-subscription by focusing on updating the expiration.

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 advises renewing well before expiry to avoid missing notifications and mentions that max extension varies by resource type. It implies usage for existing subscriptions nearing expiration but does not explicitly state when not to use it or provide alternative tools.

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