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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, non-open-world, so the safety profile is covered. The description adds genuinely new behavioral context beyond them: the call is free, it does not consume the monthly change limit, and an identical read inside 30 seconds may return stale data (with data_age_seconds as the tell). That is substantive disclosure.

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 three-read list is dense and well structured, but the lead sentence about Meta accounts earns nothing and actively misleads, and the passing reference to 'every router' and 'get_tool_schema' is never grounded. Front-loading a wrong claim is the worst possible use of the most prominent position.

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?

With no output schema, the description carries the burden of describing returns and does so for all three operations (name/number/currency/time zone/status; status/type/budget; spend/impressions/clicks/conversions/revenue). Missing only date-range or pagination mechanics for the performance read, which the agent would need to guess.

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 baseline is 3. The description goes beyond the schema by enumerating the concrete valid values for tool_name (microsoft_account_summary, microsoft_list_campaigns, microsoft_performance) and giving a worked execute payload, information the schema leaves as an open string.

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 sentence says 'Reads Meta ad accounts,' which flatly contradicts the tool name (microsoft_ads_read) and title, and is especially dangerous in a sibling set that also contains meta_ads_read and google_ads_read. The subsequent enumeration (microsoft_account_summary, microsoft_list_campaigns, microsoft_performance) is specific and does make the real scope clear, so the purpose is eventually recoverable, but the first thing an agent reads is wrong.

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?

It explains the internal action split usefully: list_tools to discover operations (free, no account call) versus execute to run a read. However it never says when to choose this tool over google_ads_read or meta_ads_read, which is the critical routing decision given the sibling set — and the mislabeled 'Meta' opening actively pushes the agent toward the wrong sibling.

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