Create signal

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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false. The description adds useful constraints like the 8KB payload limit and the source/type validation rules, plus the happened_at default-to-now behavior. But it doesn't fully disclose the full behavioral surface for a mutation tool - e.g., whether idempotency is guaranteed, any rate limits, or what happens on duplicate signals.

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?

A single compact paragraph that front-loads the core purpose, then efficiently lists the optional parameters with their types and defaults. Every sentence earns its place; there's zero padding. The enum constraints and format examples are packed into a concise but complete description.

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 create-type tool with 9 params (only 2 required), the description covers the essential semantics well: required source/type constraints, optional happened_at, url, severity, and payload limits. It would benefit from noting whether idempotency_key provides deduplication guarantees, but given the high schema coverage (89%), enums on 2 params, and default behaviors documented, the completeness is strong for the tool's complexity.

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 high at 89%, so the schema carries most of the parameter documentation weight. The description adds value by explaining the 'type' pattern examples ('deploy.completed', 'cms.page_updated'), source enum values, and specifying event context. However, it doesn't elaborate on the idempotency_key purpose or keyword_id semantics beyond schema, which the schema describes reasonably well.

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?

Description uses a specific verb+resource ('Ingest a signal') and clearly defines the resource as an external event (deploy, CMS content change, or custom API event) explaining ranking movements. It distinguishes itself from sibling tools by its unique purpose of creating signals versus reading/searching them (list_signals exists as sibling).

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?

The description clearly states it's for ingesting external events that may explain ranking movements, giving concrete examples (deploy, CMS content change, custom API event). It implies this is for signaling the system about external events but doesn't explicitly contrast with alternatives or state when NOT to use it. However, the sibling list_signals clearly pairs with it, and the 'key-scoped project' scoping gives context.

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