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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds minimal behavioral context: it specifies the post must be published and the platform must be supported. It does not discuss rate limits, auth, or error conditions, but given annotations, the bar is lower and this mild addition is acceptable.

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 two concise sentences with no redundant information. It front-loads the core action and result, making it easy to scan. Every sentence earns its place.

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 read-only analytics tool with a full output schema and complete parameter documentation, the description is sufficiently complete. It identifies the post-level scope and supported platforms, which helps selection. It could add a note about needing prior setup via list_analytics_sources, but the schema parameter descriptions already cover that linkage, so the overall context is adequate.

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 the baseline is 3. The description does not add additional parameter-level meaning beyond what the schema already provides; it only mentions 'analytics source' which loosely references channel_id and platform. Since the schema already documents parameters thoroughly, the description adds little extra value.

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 tool fetches analytics for a published Postly post, using a specific verb ('Fetches') and resource ('analytics for a published Postly post'). It also mentions returning metrics, and the title 'Get Post Analytics' aligns with this. This distinguishes it from sibling tools like account analytics or publishing activity.

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 implies usage for post-level analytics but does not explicitly contrast with alternatives like postly_get_account_analytics. It states 'for a published Postly post on a supported platform,' giving context, but lacks explicit when-to-use or when-not-to-use guidance. Sibling names help, but the description itself offers only implied usage.

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