Meta pixel health

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is fully covered by structured data. The description adds the warning conditions (never fired, silent >24h, no Purchase), which is some behavioral disclosure, but it says nothing about rate limits, auth requirements, or how empty/nulls are handled. The added context is modest against already-rich annotations.

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 front-loaded sentence that names the tool then lists its outputs and warning triggers with no filler. It is dense but readable; the parenthetical event examples and warnings are the only mild padding.

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 job of describing return values, and it does so by enumerating the metrics and warnings produced. Combined with 100% schema coverage on inputs and full annotation coverage, an agent has enough to call and interpret it; only explicit usage routing is 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 all three parameters are already documented in the schema, including defaults and the 1-30 bound. The description only echoes `days` as the counting window and adds no semantics for pixel_id or client_id beyond what the schema states. 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?

Specific verb+resource (pixel health) with an explicit enumeration of what is surfaced: last fire time, availability, automatic matching, and per-name event counts. An agent can distinguish this diagnostic tool from metric-oriented siblings like meta_insights or meta_dataset_quality by content. It stops short of naming a sibling, so 4 rather than 5.

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?

Usage is implied: the output list (fire times, availability, warnings for never fired / silent >24h / no Purchase) tells an agent this is a pixel-diagnostics call. There is no explicit when-to-use statement, no when-not guidance, and no routing to or away from alternative tools.

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