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

Annotations cover only the safety profile (readOnly, idempotent, non-destructive, closed-world). The description adds substantial behavior beyond that: the per-entry return fields, the failure taxonomy (error, silent fall-forward, delisting, unsupported), silent-failure flagging, replacement version, source URL with read date, other_dates/date_note conflict handling, and the explicit reasons a pair may return no entry.

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 question-style lead is well front-loaded and the return semantics are worth stating, but the passage is a dense single block and the provider coverage list ('Covers Shopify, HubSpot, Meta Graph...') restates providers already enumerated in the opening example list. That redundancy costs it against a tight definition.

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?

There is no output schema, so the description must carry the return contract, and it does: field-by-field contents, conflict handling via other_dates/date_note, and the three reasons an unmatched pair returns empty. For a read-only lookup tool this leaves nothing an agent needs 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 coverage is 100%, so the provider/version/api fields and their valid values are already documented structurally. The description's version examples (2025-10, v21.0, xml-rpc, ews, 2024-06-20) largely duplicate the schema's, and it never mentions the optional 'api' narrowing field, so it adds only marginal value. Baseline 3 applies when the schema does the heavy lifting.

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 opening line states a precise verb-plus-resource job: given provider/version pairs your code pins, return when each version stops working and what happens then. It lists concrete provider/version examples (shopify 2025-10, meta v21.0, stripe 2024-06-20) and names the scope, so an agent can instantly separate it from siblings like agentcheck_model_retirements.

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 when-to-use case ('when does the API version this code pins stop working') and the exact input shape are explicit, and it clarifies that no API key is needed. It never names a sibling to prefer or an exclusion condition, so it stops short of full routing guidance.

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