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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so safety is covered. The description adds useful behavioral context beyond that: it discloses the return format ('Markdown help text covering quick-start, tenant_id requirement, cart session persistence...') and the dual behavior of tool_defs as a disclosure read.

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?

After a strong first sentence the text becomes a dense, winding paragraph mixing CO 529 compliance disclosure, parameter mechanics, prompt-library routing, and return values. Phrases like 'Also the CO 529 disclosure read:' are hard to parse and bury the call-to-action; much of the content repeats schema/annotation data rather than front-loading the key instruction.

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 zero-required-param read-only helper with no output schema, the description explains what it returns and what the guide covers, so an agent has enough to call it correctly. The over-long disclosure text is extra rather than missing, and annotations carry the safety profile.

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 parameter is already documented. The description restates the tool_defs options ('pass {"tool_defs":"all"} (or one tool name)') and adds an example, but adds no syntax or meaning beyond what the schema provides. 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?

The opening sentence gives a clear verb+resource: 'Get usage instructions for the MCP federation,' and goes on to specify what the guide covers (product IDs, auth flow). It is distinguishable from siblings like federation_act or introspection_prompt_library, though the middle section drifts into routing detail rather than staying on purpose.

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 gives explicit timing ('CALL THIS FIRST to understand how to use tools correctly') and routes the agent to concrete alternatives ('search it with introspection_prompt_library, run one with federation_prompt_run', 'invoke those directly by name, or through federation_act from list-gated clients'). No explicit when-not-to-use, but the context is clear.

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