read_messages

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

With no annotations, the description carries the full burden, but it does disclose two real traits: results come from a local cache (no network fetch) and access is restricted to an 'allowlisted' chat. It does not state read-only nature explicitly, pagination/ordering behavior, or what happens when the cache is empty or the chat is not allowlisted.

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 front-loaded sentence with no filler. The scope constraint (recent, cached, single allowlisted chat) appears immediately.

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 two-parameter read tool with no output schema and no annotations, the description establishes the source (cache) and scope but leaves the limit semantics, default paging, result ordering, and error conditions unspecified. Adequate but with clear gaps.

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% for two parameters. The description only weakly implies that chatId targets a single chat and that recency is bounded, but it says nothing about the 'limit' parameter, its 1-100 range, or how limit interacts with 'recent'. The schema does the heavy lifting and the description does not compensate.

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?

Clear specific verb (read) and resource (messages) with meaningful scope qualifiers: 'recent' and 'locally cached'. It implicitly distinguishes itself from fetch_message_history (network/history) and search_messages (query-based), but never names a sibling, so differentiation requires inference.

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?

The phrase 'locally cached' and 'recent' implies when this is appropriate versus fetching history, but there is no explicit when-to-use or when-not-to-use statement and no sibling is named. Usage is inferable rather than stated.

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