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

Annotations already cover read-only, open-world, and non-destructive behavior, so the bar is lower. The description still adds genuine context: no authentication is required, results are paged, and listing has no side effects (no follow, no post access). It does not mention rate limits or what 'active' means, so it stops short of a 5.

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?

Four sentences, each carrying distinct information: scope, filtering, pagination/routing, and the no-side-effect caveat. The key constraint (no sign-in, no follow) is front-loaded rather than buried.

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?

An output schema exists, so return-value documentation is unnecessary. For a read-only paginated browse tool with all three params schema-documented and safe annotations, nothing an agent needs in order to call it correctly is missing.

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 the schema already documents limit, nextToken, and minFollowers. The description restates the follower filter and the continuation token, which is mildly useful for intent but adds no syntax or constraint detail beyond the schema. Baseline 3 is appropriate.

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 (list) plus resource (active public streams in the Synoptic catalog) and a precise scope ('one page', 'without signing in'). It is clearly distinguishable from siblings like streams_following, streams_created, and search.

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?

Explicitly routes the agent: use nextToken to continue browsing, search to find a source or topic, get_stream to inspect a result. It also states the negative case – listing a stream does not follow it or grant access to its posts – which prevents a common misuse.

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