subscribe

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

With no annotations, the description carries the full burden of disclosing behavioral traits. It mentions the quota cost, which is useful, but fails to disclose idempotency, handling of duplicate subscriptions, authentication requirements, or any side effects beyond the action itself.

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 two short sentences, front-loaded with the primary action and followed by the cost. No unnecessary words or redundant details are present.

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?

The tool is simple with one parameter and no output schema, so extensive description is not required. However, the description lacks context about side effects, error conditions, or prerequisites. It is minimally sufficient but not fully complete for an agent encountering the tool cold.

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 provides a clear description of channelId, and the tool description adds nothing beyond what the schema states. With 100% schema coverage, the baseline of 3 applies, as no further parameter meaning is introduced.

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 'Subscribe to a channel' uses a specific verb and resource, unambiguously identifying the action. It clearly distinguishes itself from sibling tools like 'unsubscribe' and 'list-subscriptions'.

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. It omits any exclusions, prerequisites, or context that would help an agent decide between subscribing and other related actions like listing or unsubscribing.

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