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

Annotations already declare destructiveHint=false and openWorldHint=true, so the bar is lower, yet the description adds a genuinely important trait beyond them: pixels created here cannot be deleted via API, making the action effectively irreversible. It also discloses what the call returns (ID + install snippet), which annotations cannot convey.

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?

Three tight blocks: purpose + return value, then a warning, then a parameter note. Front-loaded and free of filler. The parameter note is slightly disconnected from the opening sentence but nothing is wasted.

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?

An output schema exists, so return shape need not be spelled out, but the description still names the key outputs. For a create operation with no delete path, the irreversibility warning plus the duplicate-check instruction covers the main risks; only the 'name' parameter semantics remain unaddressed.

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 0%, so the description must carry both parameters. It explains 'workspace' well (client workspace slug, optional when only one workspace exists) but says nothing about 'name' — whether it is the display name, a required unique label, or its constraints. Half the parameter surface is covered.

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?

States a specific verb and resource ('Neues Meta-Pixel (Dataset) im Ad-Account anlegen') plus the concrete return value (Pixel-ID und Basis-Einbau-Code). It is immediately distinguishable from siblings like meta_list_pixels or meta_pixel_stats, which read rather than create.

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?

Gives an explicit precondition and alternative: check with meta_list_pixels first, because the API offers no delete. That is real routing guidance. It stops short of explaining other context (which ad account is targeted, workspace selection nuances beyond the slug note), so it is strong but not exhaustive.

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