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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds that the returned program is complete ('in full', 'every requirement') and lists the content areas, which is modest value. It says nothing about behavior for a missing or invalid id.

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 short sentence, front-loaded with 'One program in full', then a compact enumeration. Nothing is wasted, though the fragment style makes it slightly less crisp than an explicit verb-led sentence would be.

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 one-parameter read with an output schema and full annotation coverage, little more is needed; the description conveys that the record is exhaustive rather than summary-level. Missing only edge-case behavior such as not-found handling.

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 the schema itself explains that the id comes from search_credits or credits_for_stack. The description adds no meaning about the id beyond what the schema already provides, 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?

The description identifies a single-resource fetch and enumerates what the record contains (offer, eligibility, requirements, duration, links), which distinguishes it from list-style siblings like search_credits and credits_for_stack. It reads as a noun phrase rather than a verb+resource statement, so it stops short of an explicit 'retrieve one credit program by id'.

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?

There is no when-to-use guidance: nothing says to call this after search_credits, nor that it should be used instead of get_offer for offer-only details. The only routing hint ('A program id from search_credits or credits_for_stack') lives in the schema, not the description.

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