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

Annotations already declare readOnlyHint=true and openWorldHint=false, covering the safety profile. The description adds useful behavioral context — the response is localized ('requested language') and includes both original text and structured fields. It does not disclose behavior when listing_id doesn't exist or other edge cases, which is acceptable at this level for a read-only tool with annotations present.

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 sentence with no fluff. Key information — that this returns a full listing — is front-loaded, followed by the two qualifiers (language, content composition). Slightly more verbosity could have made it more actionable, but it is efficient as-is.

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 simple read tool with annotations and a 2-parameter schema, the description is nearly adequate: it states what is returned. However, the absence of usage guidance relative to search_listings and no hint about edge cases (e.g., invalid listing_id) leaves it slightly incomplete. A mention of 'use with search_listings for discovery' would round it out.

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 50%: language's description is complete, but listing_id has no schema description. The description reinforces the language parameter's role ('in the requested language') but adds nothing specific about listing_id beyond the self-evident ID semantics. Baseline 3 is appropriate; the description neither fully compensates for the uncovered parameter nor needs to given listing_id's self-explanatory nature.

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 communicates that this tool returns a complete ('full') listing, with original text and structured fields, in a requested language. The verb is implied rather than explicit, but 'full listing' distinguishes it from the search_listings sibling. It could be more actionable ('Retrieves a single listing by ID'), but the intent is clear.

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?

No guidance is given about when to use this tool versus search_listings, and no exclusion conditions are stated. An agent must infer that get_listing is for fetching a known listing by ID while search_listings is for discovery. This is a real gap given the sibling exists.

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