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

Goes well beyond the annotations by spelling out downstream consequences: removed targets stop appearing in stream reads, post searches, WebSocket delivery, and app feeds after reconnect, and cascade into collection sources (deleting sources left empty). It also discloses the target-allowance constraint, the format-match requirement, and the explicit non-guarantee ('does not purchase access or confirm that targets are collected').

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?

Front-loads the core action and keeps every sentence load-bearing, but the paragraph is dense with long compound sentences that could be split or trimmed. Length is largely justified by the cascading destructive behavior, so it avoids padding.

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 destructive, subscription-gated mutation with an output schema and rich annotations, the description covers prerequisites, side effects, format constraints, and non-goals. Return values are correctly left to the output schema rather than re-explained.

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 coverage is 100%, so the schema already documents add/remove/streamId thoroughly, setting a baseline of 3. The description adds genuine meaning by characterizing what targets are (accounts, channels, repositories, keywords) and pointing to get_stream for the required format, though it largely reiterates the schema's own retention and format notes.

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 (add or remove) on a specific resource (targets in the signed-in user's selection on a Synoptic custom-target stream) and clarifies it preserves the other targets, which distinguishes it from set_stream_custom_targets. An agent can tell what it does and what it doesn't replace without opening a schema.

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?

Gives clear preconditions—requires following the stream and an active direct subscription—and the 'keeping other targets' phrasing implicitly routes to the set_ alternative. It never explicitly names a sibling tool or states when NOT to use it, so it stops short of full when-to-use/when-not guidance.

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