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

With no annotations, the description carries the full burden and does well: it discloses idempotent retry semantics, a 48-hour request expiry cap, 30-day server-side retention, and that the secret travels only in the X-Context-Key HTTP header. It omits version-conflict/error behavior, which keeps it short of a 5.

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?

Four dense sentences, front-loaded with the core action before the parameter mechanics. Minor formatting defects ('at most48hours', 'text30days') slightly hurt readability but no sentence is wasted.

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 5-required-param mutation tool with no annotations and no output schema, the description supplies the key operational context (upsert semantics, idempotency, expiry, retention, auth channel). Remaining gaps are error/conflict handling and the exact meaning of 'key'.

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 coverage is 0%, so the description must compensate, and it explains three of five parameters substantively: expectedVersion (0=create, else last read version), requestExpiresAt (unchanged on retries, max 48h), and idempotencyKey (unchanged on retries). It leaves 'key' ambiguous (the X-Context-Key note concerns the header, not clearly this param) and 'value' unexplained, so it does not fully close the gap.

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 and resource ('Save selected guest text'), and the 'without registration' qualifier distinguishes it from registered-agent writes. Sibling tools read_guest_context/delete_guest_context imply the read/delete counterparts, but the description never explicitly routes between them.

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 genuinely useful calling conditions ('Zero expectedVersion creates; otherwise pass the last read version' and retry guidance for requestExpiresAt/idempotencyKey), which is implied how-to-use. However it never states when to choose this tool over read_guest_context, delete_guest_context, or guest_context_limits, so alternatives remain unaddressed.

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