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

Goes well beyond the readOnly/openWorld annotations by disclosing visibility rules (public streams without sign-in; private streams only for owners, followers, subscribers, invitees) and a non-obvious ordering caveat ('ordered by follower count, not relevance'). It also names the returned fields, which is genuinely useful behavioral context.

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 purpose, then layers match scope, visibility, ordering, and return fields, with the get_stream pointer last. Every sentence carries information, though it is denser than strictly necessary for a search tool.

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?

Despite an existing output schema, the description still names the key returned fields, and it fully covers matching scope, visibility, ordering, and the follow-up tool. Nothing needed to invoke or interpret a call 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 limit, offset, and the query semantics are already fully documented in the schema. The description's matching-scope sentence largely mirrors the query parameter's own description and adds no new parameter detail, so the baseline 3 applies.

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 and resource ('Search the Synoptic stream catalog by keyword') and immediately scopes what is matched. It distinguishes itself from the sibling search_stream_posts by explicitly declaring it does 'not search post text', so an agent can route correctly without opening either 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 a clear next-step alternative: 'Use get_stream to inspect a result before reading posts or configuring targets', which tells the agent when this tool ends and another begins. It also implicitly excludes post search, but never names search_stream_posts explicitly as the alternative, leaving that routing to inference.

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