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

Goes well beyond the annotations: it enumerates concrete side effects (unfollows followers, sends notifications, removes the stream from collections, API key publish permissions and source routes) and states irreversibility ("cannot be undone"). The annotations only supply destructiveHint/idempotentHint, so this detail is genuinely additive.

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?

Three sentences, front-loaded with the action and scope, followed by consequences and restrictions. Every clause carries operational information; nothing is filler.

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 single-parameter tool with an output schema, the description covers everything an agent needs: eligibility, side effects, irreversibility, and the blocked case. Return values are already handled by the 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?

Schema coverage is 100%, so baseline is 3, but the description adds real constraint semantics: the ID must be exact and must belong to a free stream the caller owns. That is more than restating the schema's "ID of a free stream you own, from streams_created."

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+resource ("Delete an owned free stream") and immediately scopes it to free streams the caller owns, which cleanly separates it from the other delete_* siblings (delete_ai_filter, delete_collection, delete_stream_deck, delete_terminal_tab). An agent can pick this tool without opening any 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 when-to-use conditions (owned, free stream) and an explicit when-not (paid streams must be deleted in the Synoptic app), plus the precondition that the exact stream ID is required. It stops short of routing the agent to the nearest alternative, unfollow_stream, for the non-destructive case.

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