Discover Substack Subscriptions

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

With no annotations, the description should disclose critical behavioral traits like side effects, authentication requirements, and output format. It only mentions using an authenticated profile, but does not clarify if the tool is read-only, whether it modifies data, or what triggers the 'discovery' process.

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 a single concise sentence, which is efficient. However, it could be slightly more structured to include context about expected results without becoming verbose.

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 no output schema, the description should explain return values or behavior beyond the action. It does not state what 'discover' returns (e.g., list of publication names, URLs, or metadata), leaving a significant gap for the agent.

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 tool has zero parameters, so the description adds no param-specific meaning. According to the rule, 0 parameters yields a baseline of 4; the schema coverage is 100% and no additional param info is needed.

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 clearly states the tool discovers subscribed publications using an authenticated browser profile, which is a specific verb-resource pair. It is distinct from sibling tools, none of which mention 'discover' or 'subscriptions' directly.

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 listing posts or syncing. The description does not mention prerequisites or context for invocation.

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