List signals

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds ordering (newest first), per-item fields, the effect of response_format, and the next_cursor pagination contract in structuredContent. It does not discuss page-size limits or cursor expiry, but the added behavioral context is well beyond the annotations.

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 tight sentences, front-loaded with the definition and ordering before filters and follow-up actions. The closing structuredContent summary is slightly redundant given a dedicated output schema, which keeps it from being maximally economical.

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 filtered, paginated list tool it covers everything an agent needs: what a signal is, default ordering, filter dimensions, response-format effects, pagination via next_cursor, and the follow-up tool for state changes. Return-value explanation is redundant with the output schema but not harmful.

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% and the schema already spells out limit bounds, cursor usage, the status enum meanings, and what detailed returns, so the description mostly restates rather than extends it. Minor value is added by clarifying that scout_id refers to a global scout and that status "new" means unread, but with full schema coverage the baseline of 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 ("Lists signals") and disambiguates with concrete examples ("events scouts found, such as a funding round or a leadership change") plus ordering ("newest first"). An agent can distinguish this from siblings like heliyos_scouts_list or heliyos_signals_mark_read 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 real routing guidance: scouts come from heliyos_scouts_list, and read-state changes belong to heliyos_signals_mark_read, which steers the agent away from misusing this tool. It does not state exclusions (e.g., when to prefer a records or interactions listing instead), so it falls short of a full when/when-not treatment.

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