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

Adds substantial context beyond the thin annotations: it flags the mutation ('MUTATES Text-Em-All data'), clarifies the non-effect ('creates a DRAFT — does NOT send anything'), gives the underlying endpoint, and describes the return shape. The only mild tension is that the destructiveHint=true annotation reads stronger than 'does not send anything'; a sentence on draft persistence/cleanup would have closed the loop.

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?

One tight paragraph, front-loaded with the mutation warning and the key negative constraint ('does NOT send anything'), then the alternative, then the API/return details. No sentence is redundant.

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?

No output schema exists, but the description compensates by naming the salient return field ({ SingleSignOnUrl, ... }) and explaining the follow-up workflow in the UI. Combined with the required/minItems constraints already in the schema, an agent has everything needed to call it correctly.

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% and both properties (contacts, fields) are already documented in-schema, including the PascalCase passthrough semantics for 'fields'. The description only restates 'with the given contacts' and adds no format, cardinality, or merging detail beyond the schema, so the baseline 3 applies.

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 ('stages a broadcast with the given contacts') plus the concrete output ('returns a single-sign-on URL to finish + send it in the Text-Em-All UI'). It also explicitly distinguishes itself from the sibling create_broadcast, so an agent can route between them without opening either schema.

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 conditional: 'Safer than create_broadcast when a human should review before sending.' It names the alternative and the condition that selects it, which is exactly what the routing decision requires.

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