purge_old_messages

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

No annotations are provided, so the description carries full behavioral burden. It discloses the default retention source (retention_max_age_days, 180 days) and that it returns a purged count, but omits critical safety facts for a destructive mutation: that dry_run defaults to true, whether the delete is reversible, and what authorization it requires.

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?

Three tight sentences with the core action front-loaded and no filler. Every clause carries information, though the return-count sentence is somewhat redundant given an output schema exists.

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?

An output schema exists, so return values needn't be restated. However, for a destructive purge tool with zero annotations and 0% param coverage, the description is under-complete: it avoids the dry_run safety default and irreversibility, which an agent needs before calling.

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%, so the description must compensate for all three params. It partially explains max_age_days via the retention default, but says nothing about project_key (the required param) or the pivotal dry_run flag, leaving most parameter semantics undocumented.

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 + resource ('Delete messages older than the configured retention period'), which is clearly distinguishable from sibling read tools like search_messages or fetch_inbox. It does not explicitly name a sibling it competes with, but the destructive retention-scoped scope is unambiguous.

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 explicit when-to-use guidance, no prerequisites (e.g., permissions), and no mention of alternatives such as archiving vs purging. The description only implies the retention-cleanup context without stating conditions for invoking it.

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