Received webhook events

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

The description adds significant behavioral context beyond the annotations: it reads from an 'in-process buffer filled by the webhook receiver', does NOT call the Avito API, and does NOT mark anything as read. This aligns with the annotations (readOnlyHint=true, destructiveHint=false, idempotentHint=true) and provides crucial details about side effects and data source.

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?

The description is concise (three sentences) and front-loaded with the core purpose. Every sentence adds value: purpose, operational details, prerequisites, filters, and cross-reference to status tool. No fluff or repetition.

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?

Given the tool's simplicity (3 params, full schema coverage, no output schema), the description covers prerequisites, filtering, side-effect details, and references to related tools. However, the absence of an output schema means the agent might lack details on the event structure. The description mentions 'new chat messages', which gives a hint, but a richer description of the return format would improve completeness.

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% (all three parameters have descriptions). The description summarizes the parameters: 'Supports filtering by chat_id, a `since` cutoff (ISO-8601 timestamp or epoch seconds/ms), and a `limit`.' This is a helpful recap but does not add new meaning beyond the schema. Following the guidelines, baseline 3 is appropriate.

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?

The description clearly states the action ('Returns'), the exact resource ('Avito messenger webhook events'), and the context ('received by this server', 'newest-first'). It explicitly distinguishes itself from sibling tools by stating what it does NOT do (calls Avito API or marks as read), which sets it apart from related tools like messenger_get_chats_v2 or messenger_get_messages_v3.

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 specifies prerequisites: 'Requires the receiver to be enabled (set AVITO_MCP_WEBHOOK_SECRET) and Avito subscribed to the receiver URL (messenger_register_webhook).' It also references a related tool for checking status (messenger_get_webhook_status). However, it does not explicitly state when one should NOT use this tool, which would strengthen the guidelines further.

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